The atoms of different elements have what?

Answers

Answer 1
different numbers of electrons,protons, and neutrons

Related Questions

which element in period 3 has the greatest tendency to lose an electron?

Answers

The element in period 3 that has the greatest tendency to lose an electron is Sodium (Na)

Sodium is the first element in the period 3. In the periodic table, atomic size or atomic radius decreases from left to right.

We know that, higher the atomic radius higher the tendency to lose an electron by the element.  In addition to that, sodium has only one valence electron in their outermost orbitals which would be easily lost to attain a stable state.

Thus, Sodium (Na) with higher atomic radius in period 3 and one valence electron in their outermost orbitals would have the higher tendency to lose an electron.

To know more about Atomic size

https://brainly.com/question/1127028

#SPJ1

Hydrogen is 99% 1H, 0.8% 2H, and 0.2% 3H. Calculate its average atomic mass.

Answers

Just add them up bro.. 99+ (0.8*2)+ (0.2*3)= 101.2

If strontium nitrate and sulfuric acid are reacted together, what would be the resultant white precipitate that forms?

Answers

strontium sulfate is WHITE CRYSTALLINE POWDER WITHOUT A SMELL. heating steadily above 1580°C causes decomposition. Sulfur oxides and other harmful and corrosive gases are produced as a result.

Sr(NO3)2 + H2SO4 -> 2HNO3 + SrSO4 is molecular equation

SrSO4 ( strontium sulfate will precipitate )

What is strontium sulfate used for? Glass and ceramics both employ it as a red colorant. Zinc is refined using it. It is also employed in flares.strontium sulfate is WHITE CRYSTALLINE POWDER WITHOUT A SMELL. heating steadily above 1580°C causes decomposition. Sulfur oxides and other harmful and corrosive gases are produced as a result.At the quantities normally seen in the environment, stable strontium has no negative effects on people. Stable strontium only exists in one chemical form, strontium chromate, which is extremely dangerous to breathe in due to poisonous chromium rather than strontium itself.

To learn more about :  Strontium

Ref : https://brainly.com/question/4249120

#SPJ9

A project is estimated to take 300 hours but can be completed whenever the team has spare time. Three employees will take turns working on the project. The first employee completes one-third of the project. The second completes one-fifth of the work remaining. The third completes one-half of the work remaining. How many hours are left for the fourth employee to complete?

Answers

The number of hours left for the fourth employee to complete would be 80 hours.

Algebraic problem

The total number of hours to complete the entire project = 300 hours.

The first employee completes one-third of the project:

1/3 x 300 = 100 hours.

The remaining hours would be: 300 - 100 = 200 hours.

Now, the second employee completes one-fifth of the work remaining:

1/5 x 200 = 40 hours.

200 - 40 = 160 hours.

A total of 160 remain after the 2 employees have completed their work.

Now, the third employee completes one-half of the remaining work:

1/2 x 160 = 80 hours.

The total number of hours left for the fourth employee to complete is, therefore, 80 hours.

More on algebraic problems can be found here: https://brainly.com/question/15167098

#SPJ1

Which is the equation for a machine's efficiency? (1 point)
O Efficiency=input energy
O Efficiency=
input energy
output energy
output energy
input energy
-
-
output energy
100
O Efficiency
O Efficiency=input energy + output energy
100

Answers

The efficiency of the machine can be obtained from the expression;

Work output/ work input * 100/1

What is the efficiency?

The term efficiency has to do with the way in which energy is converted to a good use in the machine. Let us note that a machine is efficient when most of the work done by the machine has been put to a good use. This is shown by a very high value of the efficiency.

Let us note that a machine can only be able to do a useful work when the efficiency of the machine is high and the machine is able to do quite a whole lot of useful work as we shall see below.

As such, we define the efficiency as the ratio of the work input to the the work output multiplied by a hundred. We are now trying to obtain the equation that can more aptly be said to be the efficiency of the machine.

earn more about the efficiency of a machine:https://brainly.com/question/11752408

#SPJ1

How many grams are in 0.90 mol of lead?

Answers

Answer:

[tex]186.3\text{ g}[/tex]

Explanation:

Here, we want to get the mass of 0.90 mol of lead

To get the mass, we use the following formula:

[tex]\text{ mass = No of moles }\times\text{ atomic mass/molar mass}[/tex]

The atomic mass of lead is 207 amu (this is obtainable from the periodic table)

Thus, we have the mass as:

[tex]0.90\text{ }\times\text{ 207 = 186.3 g}[/tex]

Which of the following is the most basic?

A solution with [OH-] = 1.0×10-10.
A solution with [H+] = 1.0×10-10.
A solution with a pH of 6.
A solution with [OH-] = 1.0×10-6.
A solution with [H+] = 1.0×10-6.

Answers

Answer:

A solution with [H+] = 1.0×10-10

Explanation:

Using the equations: pOH = -log([OH-]), pH = -log([H+]), and pH + pOH = 14

To find the most basic solution, find the pH or the pOH.
The pOH of solution 1 is 10, which means the solution is acidic (pH = 4)
The pH of solution 2 is 10, which is quite basic
The pH of solution 3 is 6. slightly acidic
The pOH of solution 4 is 6, and has a pH of 8. Slightly basic
The pH of solution 5 is 6, slightly acidic

Out of all of these, solution 2 and 4 are basic. Solution 2 has a pH of 10, which is more basic than solution 4 with a pH of 8

QUESTION 13
What mass of 45.0% Ba(NO3)2 solution contains 40.0 grams of Ba(NO3)2?

Answers

88.9 grams of 45.0% Ba(NO3)2 solution contains 40.0 grams of Ba(NO3)2?

What is barium nitrate ?

The toxic and colorless inorganic substance with chemical formula

Ba(NO3)2 is barium nitrate. The exposure of this compound to flame gives a green-colored flame. The most common use of this compound is pyrotechnics.

Let x grams of Ba(NO₃)₂, solution contains 40 grams Ba(NO₃)₂

Then, 45% of  x = 40

[tex]\frac{45}{100}[/tex] × x = 40

x = 88.9 grams

Thus we can conclude that  88.9 grams of 45.0% Ba(NO3)2 solution contains 40.0 grams of Ba(NO3)2

Learn more about mass percent at https://brainly.com/question/13896694

#SPJ13

Is this correct your basically dividing and multiply and can you create a graph of this data table? Pleaseee help I’m so lost

Answers

According to the given table, the last three spaces in "Calculate constant PV" are:

[tex]\begin{gathered} 15.0\cdot69.9=1048.5 \\ 17.5\cdot58.8=1029 \\ 20.0\cdot50.7=1014 \end{gathered}[/tex]

We will plot a graph using the values of volume in the x axis, and the values of pressure in the y axis. Once we plot each of the points, we will obtain this graph:

What is the ionization energy of 30 g lithium when it is vaporized?
(1st ionization energy = 245 KJ/mole)

Answers

10.58 * [tex]10^{-2}[/tex] KJ ionization energy is needed to vaporized lithium.

What is ionization energy or enthalpy?

Ionization energy may be defined in basic words as a measurement of an atom's or ion's propensity to give up an electron or the difficulty in removing an electron from one.

Mass of lithium = 30 gm

Ionization enthalpy of lithium = 245 KJ/mole

Now calculate moles of lithium = [tex]\frac{Given\ mass}{molar\ mass}[/tex]

no. of moles = [tex]\frac{30}{6.941}[/tex]

no. of moles = 4.32 moles

For 1 mole of lithium ionisation enthalpy = 245 KJ

for 4.32 mole of lithium ionisation enthalpy = 245 *4.32 KJ

                                                                        = 10.58 * [tex]10^{-2}[/tex] KJ

To know more about ionization enthalpy refer to,

https://brainly.com/question/20658080

#SPJ9

13) If the oxidation number of nitrogen in a certain molecule changes from +2 to -2 during a reaction, how many electrons are gained (or lost) by each nitrogen atom?

Answers

Answer:

4 electrons were gained

Explanation:

Here, we want to get the number of electrons gained or lost

From what we have, there was a change from a positive value to a negative one

Since electrons are negatively charged entities, it means that the nitrogen atoms gained electrons.

For the change to have occurred, there must have been a matching of two electrons initially, then another two electrons

Thus, we have the total number of electrons gained as 4

A 11.77 g sample of a compound contains 7.51 g of iron, Fe, 1.39 g of phosphorus, P, and oxygen, O. Calculate the empirical formula for the compound.

Answers

Considering the definition of empirical formula, the empirical formula for the compound is Fe₃PO₄.

Definition of empirical formula

The empirical formula is the simplest expression to represent a chemical compound, which indicates the elements that are present and the minimum proportion in whole numbers that exist between its atoms.

Empirical formula in this case

In this case, in first place you need to convert the number of grams given into percentage as follow:

Iron (Fe): (7.51 g÷ 11.77 g)× 100= 63.81%Phosphorus (P): (1.39 g÷ 11.77 g)× 100= 11.81%Oxygen (O): (2.87 g÷ 11.77 g)× 100= 24.38%

Assuming a 100 grams sample, the percentages match the grams in the sample. So you have 63.81 grams of iron, 11.81 grams of phosphorus and 24.38 grams of oxygen.

Then it is possible to calculate the number of moles of each atom in the molecule, taking into account the corresponding molar mass:

Iron (Fe): 63.81 g÷ 55.85 g/mole= 1.14 molesPhosphorus (P): 11.81 g÷ 31 g/mole= 0.38 molesOxygen (O): 24.38 g÷ 16 g/mole= 1.52 moles

The empirical formula must be expressed using whole number relationships, for this the numbers of moles are divided by the smallest result of those obtained. In this case:

Iron (Fe): 1.14 moles÷ 0.38 moles= 3

Phosphorus (P): 0.38 moles÷ 0.38 moles= 1

Oxygen (O): 1.52 moles÷ 0.38 moles= 4

Therefore the Fe: P: O mole ratio is 3: 1: 4

Finally, the empirical formula is Fe₃P₁O₄= Fe₃PO₄.

Learn more about empirical formula:

brainly.com/question/27948788

brainly.com/question/21081934

brainly.com/question/5115389

brainly.com/question/4594902

#SPJ1

How were indentured servants different than slaves? | A:
Indentured servants were considered property of their owner. | B:
Indentured servants were freed after a period of time. | C:
Indentured servants were forced to work with no pay. | D:
Indentured servants were treated unfairly. | Someone help plsss

Answers

Answer:

C

Explanation:

Indentured servants worked to pay off a debt and were released after a certain amount of time as the debt has been payed off

b they were eventually freed usually between 4-7 years

Calculate the [OH-] given pH of 9.9

Answers

Answer

pOH = 4.1

Explanation

Given:

pH = 9.9

Required: The concentration of OH-

Solution

pH + pOH = 14

9.9 + pOH = 14

pOH = 14-9.9

pOH = 4.1

How many molecules of acetylene (C2H2) are in 1.79 moles of acetylene

Answers

The simplest alkyne chemical molecule, known as acetylene chemically, is C2H2. Ethyne, Narcy Len, and Vinylene are other names for acetylene.

C2H2 has how many moles?

Two. C2H2 molecules contain 2 carbon atoms each. As a result, there are 2 moles of carbon atoms in every mole of C2H2. You may determine how many moles of an element there are in one mole of a compound by looking at the subscripts in any formula.

The C2H2 chemical formula

Acetylene has the extended chemical formula CHCH and the chemical formula C2H2. Acetylenes' molar mass can be expressed as 26.04 g/mol-1.

Grams Acetylene = 46.60673120000018

Mol = 1.79.

C2H2 molecule

Acetylene, C2H2 / Formula is below.

To Learn more About  C2H2 chemical formula, Refer:

https://brainly.com/question/1596622

#SPJ10


Why do lunar and solar eclipses not happen every month?

Answers

They do not happen every month because the Earth's orbit around the Sun is not in the same plane as the Moon's orbit around the Earth.

The weak base ionizationconstant (Kb) for C2H302 isequal to:BAC2H3O2H] [OH-](C2H302 -][H2O]

Answers

Answer:

Option B.

Explanation:

The formula of the Kb is written by dividing with the multiplication of the concentration of the products in the numerator, and the multiplication of the concentration of the reactants in the denominator:

[tex]K_b=\frac{\lbrack C_2H_3O_2^-\rbrack *\lbrack H_2O\rbrack}{\lbrack C_2H_3O_2H\rbrack}[/tex]

23423456789098765432

Answers

366373838384774738393

Explanation:

267277777727777525256 ;)

Calculate the moles of 35 grams of ice (H₂O).

Answers

1.94 moles of 35 grams of ice (H₂O).

18 g of ice = 1mol.

Therefore,

35 grams of ice  = 35/18

35 grams of ice  = 1.94 moles.

What is molar mass ?

Molar mass (M) is a physical property defined as the mass of a certain element or molecule per mole of  substance. Since a mole is defined as the amount of a substance and substances have different masses, each element or molecule has a different molar mass. For example, if one has a dozen bricks and the other has a dozen feathers, they have the same amount of matter but very different total masses.

To learn more about molar mass , visit;

https://brainly.com/question/10157406

#SPJ13

What are some characteristics that show a tree is living?

Select all that apply.

It has no cells.
It doesn’t respond to the environment.
It grows.
It moves.
It reproduces.

Answers

It grows, moves, and reproduces
Every living thing grows, moves and reproduces.

What possible elements do emit photons on those colors when electrons decay to a ground level orbit?

Answers

Elements do emit photons on those colors when electrons decay to a ground level orbit then the each element will produce its own set of color

Photon is the tiny particle of electromagnetic radiation

Light travels as discrete packets of light called photons and each photon will be carrying a certain amount of energy then the energy carried within a photon determines then what color it is with blue photons having about twice the energy as red photon and the fact are given below

Atom has the limited set of orbital path that electron are willing to travelEach elements has its own set of orbit When electron move between orbit then they release photonMotion between a certain set of orbits results in photons with a corresponding set of energiesPhoton at different energy appear at different colorEach energy will produce its own unique set of color

Know more about color of element

https://brainly.com/question/14350185

#SPJ1

Jolie is staring at the Moon with her brother and comments that it looks "gibbous." What does Jolie mean by this
OA. The Moon looks rounded on both sides.
The Moon looks narrow.
The Moon looks narrow on one side and round on the other.
The Moon is just a small sliver.
B.
OC.
OD.

Answers

According to the given statement Jolie mean by The Moon looks rounded on both sides.

The correct option is A.

Why is it called a gibbous?

Waxing gibbous refers to a moon that is more than halfway full and continues to increase its luminous surface. Gibbous, which means "hump" in Latin, has been used for centuries to refer to rounded or convex forms, such as enlarged eyes or a camel's back.

What happens during a gibbous?

Gibbous Moon refers to the phase of the Moon when the side that faces Earth appears to be more than half-lit by the Sun but is less than fully lit. From new Moon through full moon and back, the lunar month, which is the full cycle of the Moon's stages, lasts 29 days.

To know more about Gibbous visit:

https://brainly.com/question/18214862

#SPJ13

The complete question is -

Jolie is staring at the Moon with her brother and comments that it looks "gibbous." What does Jolie mean by this

A. The Moon looks rounded on both sides.

B. The Moon looks narrow.

C. The Moon looks narrow on one side and round on the other.

D. The Moon is just a small sliver.

Help me please I begg of you pleaseeeee

Answers

Answer:

Exothermic reaction.

Explanation:

Since the products end up having a lower energy than the reactants, that means that the reaction is exothermic. It also means that this reaction released energy.

Deoxyribonucleic acid, DNA, is made of nucleotide monomers that hydrogen-bond with nucleotides on another strand of DNA to form aQuestion 12 options: β-pleated sheet. double helix. α-helix. straight chain.

Answers

DNA has a double helix structure, which is basically two chains of nucleotides that are bonded by hydrogen bonds.

It means that the correct answer is double helix.

Which two actions are examples of science influencing technology?A. Using the internet to publish and share new scientific discoveriesB. Using research about kingfishers to design a more efficient high-speed trainC. Studying how infections spread through the body in order tobetter understand bacteriaD. Using observations about plant seed structures to develop hook-and-loop fasteners

Answers

The two actions that are examples of science influencing technology are:

A) Using the internet to publish and share new scientific discoveries.

D) Using observations about plant seed structures to develop hook-and-loop fasteners. Option A and D

These examples illustrate how scientific advancements and knowledge have influenced the development and application of technology.

Using the internet to publish and share new scientific discoveries is a prime example of science influencing technology. The internet has revolutionized the way scientific information is disseminated, allowing researchers to publish their findings rapidly and share them globally.

This has facilitated collaboration, accelerated the spread of scientific knowledge, and enhanced the efficiency of scientific communication. The internet has also given rise to platforms for open-access journals and online scientific communities, enabling greater accessibility and the democratization of scientific information.

Using observations about plant seed structures to develop hook-and-loop fasteners is another instance of science influencing technology. Scientists studying the natural world have observed the mechanisms by which certain plants disperse their seeds.

One such example is the observation of burrs or burdock plants that use tiny hooks to attach to animal fur or clothing. Inspired by these observations, scientists developed hook-and-loop fasteners, commonly known as Velcro, which mimics the natural hooking mechanism of the plant seeds.

This technology has found widespread applications in various fields, including clothing, aerospace, and medicine, offering a versatile and efficient fastening solution.

These examples highlight the reciprocal relationship between science and technology, where scientific discoveries and knowledge contribute to technological advancements, while technological developments, in turn, provide new tools and capabilities for scientific research and exploration.

For more such question on scientific discoveries visit:

https://brainly.com/question/28207278

#SPJ8

Continuing the previous equation for set up Based on the balanced chemical reaction if desired to produce 2.50g of NaCl in this reaction, how many grams of Na2CO3 would need to be used

Answers

Set up:

Na2CO3 + 2 HCL ------> 2 NaCl + H2O + CO2

105.99

Arrange the following elements in order of increasing size: Al, B, K, and Na

Answers

Answer:

B < Na < Al < K

Explanations:

The size of elements in the periodic table increases from right to left and top to bottom down the group.

For the given question, we will arrange the elements based on atomic size.

For the given elements

• Aluminum has an atomic number of 13

,

• Boron has an atomic number of 5

,

• Potassium has an atomic number of 19

,

• Sodium has an atomic number of 11.

The increasing size will be based on their increasing atomic number and position in the periodic table.

The required increasing size will be B < Na < Al < K

How many grams of NaOH are required to neutralize 700 mL of 3.0 M HCl?

Answers

A gram of NaOH required to neutralize 700 ml HCL is 84 grams.

Neutralization or neutralization is a chemical response in which an acid and a base react quantitatively with each different. I

Moles of solute = Molarity × Liters of solution

                           = 3 × 0.7 L

                          = 2.1 mole

The molar mass of NaOH = 40

mass of NaOH = 40 × 2.1 g

                        = 84 gram.

A neutralization response may be described as a chemical reaction in which an acid and base quantitatively react together to shape salt and water as products. In a neutralization response, there's a combination of H+ ions and OH– ions that form water.

A neutralization response is when an acid and a base react to shape water and salt and includes the mixture of H+ ions and OH- ions to generate water. The neutralization of a sturdy acid and robust base has a pH equal to 7.

Learn more about neutralization here:-https://brainly.com/question/23008798

#SPJ1

The following data was collected when a reaction was performed experimentally in the laboratory.Reaction Data ReactantsProductsAl(NO3)3NaClNaNO3AlCl3Starting Amount in Reaction4 moles9 moles??Determine the maximum amount of NaNO3 that was produced during the experiment. Explain how you determined this amount

Answers

The first step to solve this question is to write and balance the chemical equation that describes the reaction:

[tex]Al(NO_3)_3+3NaCl\to3NaNO_3+AlCl_3[/tex]

According to the given information the limiting reactant is NaCl, this is because 9 moles of this reactant react with 3 moles of Al(NO₃)₃.

Use this information to find the maximum amount of NaNO₃ that was produced:

[tex]9molNaCl\cdot\frac{3molNaNO_3}{3molNaCl}=9molNaNO_3[/tex]

It means that 9 moles of NaNO₃ are produced.

In a paragraph, explain Le Chatelier's Principle, give examples

Answers

Explanation:

Le Chatelier's principle states that if a dynamic equilibrium system is disturbed by changing for example pressure, temperature, or concentration of products or reactants, the equilibrium will shift in the opposite direction to offset the change.

----

An example to understand better this principle:

Given a general reaction in equilibrium:

A (g) + B (g) <=> C (g) + D (g) ΔH < 0 (it means an exothermic reaction)

This reaction can be seen as follows:

A (g) + B (g) <=> C (g) + D (g) + energy (exothermic reaction = releases energy)

If the temperature increases or heat is added, the equilibrium will shift to the left because of the principle. (There are many examples)

Other Questions
Select the correct texts in the passage,Julian factored the expression 224 +223 - 22 - 1. His work is shown.At which step did Julian make his first mistake, and which statement describes the mistakerIStep 1224 +223 22= (2:13 + 2x2 - 1 - 1)(232(0 + 1) - 1( 1)2 (212 1)(x + 1)(x - 1)Step 2Step 3Julian should have factored (2x2 - 1) as a difference of squares,Julian incorrectly factored -1 from the second group of terms.Julian should have factored 2x from all terms instead of x.Julian incorrectly factored 2x2 from the first group of terms.O 2021 Edmentum. All rights reserved. (Question in file need help asap) What is the constant of proportionality? Using Pythagoras theorem or trigonometric ratios 3. Ed wants a career that allows to him to utilize his passion for history, presentation skills, andability to work well with others. He has chosen to plan for a career as a lawyer based on hiscareer expectationsOhigh school academicsfamily historyOjob outlook(1 point) The following table shows the points scored each game by Pat during the basketball season. Complete the following questions:1. What is the probability Pat scores between 10 and 15 points in a game? Round answer to two decimal places.2. What is the probability Pat scores 16 or more points? Round answer to three decimal places. describe how melanin in the skin plays a role in vitamin d synthesis and in the depletion of folate (folic acid). (multiple answers) Following is an excerpt from Sherwood Anderson's 1919 novel, Winesburg, Ohio.Between Elizabeth and her one son George there was an unexpressed bond of sympathy, based on a girlhood dream that had died long ago. In the son's presence she was timid and reserved, but sometimes while he hurried about town intent upon his duties as a reporter, she went into his roomIn the room by the desk she went through a ceremony that was half a prayer, half a demand, addressed to the skies. In the boyish figure she yearned to see something half forgotten that had once been a part of herself re-created. The prayer concerned that. "Even though I die, I will in some way keep defeat from you," she cried, and so deep was her determination that her whole body shook.Based on this excerpt, what seems to have inspired Elizabeth's ceremony? in addition to the presence of soft sediments, the next earthquake to strike seattle could cause extensive destruction due to the presence of How do bacteria develop antibiotic resistance?The goal of this assignment is to help students understand that bacteria are living organisms. When we use antibiotics against them to control infections and diseases, they tend to gradually start showing their resistance to that antibiotic. There are different ways bacteria develop such resistance. Sometimes they develop resistance after they come in contact with the chemical but sometimes they develop such resistance without even being exposed to that chemical. So, it is important to understand the different ways by which bacteria develop antibiotic resistance.DirectionsYou can check chapter 1 and chapter 8 for some information. You can also search the web to find information. Your paper must be around two pages long and written in the English language, with 1.5 spacing, in Times New Roman, and font 12. References should be on the 3rd page an architect creates two different blueprints for a new storage unit building. The scale from the building to the first blue print is 8ft to 2 cm. The length of a type A storage unit is 6.5 cm on the first blue print. The scale from the building to the second blueprint is 24 ft to 4cm The length of type B storage unit is 4.5 cm on the second blueprint. Which type of storage unit is longer? The radius of a circle is 9 inches. What is the length of a 45 arc? 13. There is an 80 gram mixture of material X, Y, and Z. The ratio X :Y:Z is 4/7 / 5 . If material Z is removed, what is the new weight, in gram, of the mixture?A. 11B.64C. 25D.45 I need help finding the vertex and axis of symmetry 52.5% in fraction form Why might On the Moral and Political Principles of Domestic Policy be an important historical document during this period of the French Revolution? (How might this document help historians better understand this time period?) Write the first five terms of the sequence:a(1) = 1, a(n) = 5(n-1), n 2 Which picture correctly shows the path of the reflected light ray given an object inside the focal point? It takes a printer 2.25 hours to print 1,080 pages. The printer prints pages at a constant rate. How many pages per hour does the printer print?Enter your answer in the box. Select all the correct answers.Jamel is writing a research paper arguing that media outlets promote bias and discrimination. Which two details would serve as evidence to supportJamel's claim?A. a series of social media postsB. an interview with a reporter about a news outlet's policies on editing storiesC. a chart comparing the viewership of three popular media outletsD. a research study comparing the reactions of viewers of two different news channels to a story aboutreligious discrimination most vectors have a second genetic marker that is made non-functional if an insert is in the multiple-cloning site. this disruption of the marker's function is called