Earth Science c/o Atoms

Question

 

 

If I have two Atoms, one is Mg and the other is Cl.

 

 

  Mg has 1 nucleus, the outer shell has 2 electrons, the next shell has 8 electrons, then the inner circle has 2 electrons, then the nucleus.

 

 Cl has 1 nucleius, the outer shell has 7 electrons, the next shell has 8 electrons, the inner circle has 2 electrons, the the nucleus.

 

 

1.  Which electrons have the highest energy level in each atom?

 

2.  Both atoms need a total of 8 electrons to fill their highest energy level.  How many electrons does a chlorine atom need to have a total of 8 electrons in its highest energy level?

 

3.  How many electrons does magnesium have in its highest energy level?

 

4.  Which atom is most likely to give up its electrons to another atom. Why?

 

5. a. When clorine and magnesium reat chemically, how many chlorine atoms will combie with one magnesium atom?  (consider the answers for #3 and #4)

 

    b.   what is the chemical formula of the compound that is formed?

Answer 1

1.) The highest energy electrons are those located in the valence shell, or the outermost shell. For Mg, this would be the electrons in the 3s orbital. For Cl, this would be the electrons in the 3p orbital.

 

2.) Chlorine, as a halogen (located in the column directly left of the noble gasses), has 7 valence electrons and therefore needs 1 more electron to fill its octet.  

 

3.) Magnesium, located in Column 2 (or Group 2) has 2 electrons in its valence shell. It will give up 2 electrons to have the electron configuration of Neon, as opposed to gaining 6 electrons. It will have a complete octet in the n=2 level. (2s2 2p6)

 

4.) Magnesium, as a metal, will give up its electrons. They are loosely bound to the nucleus and by losing 2 electrons, magnesium will adopt a more stable electron configuration with the 2 shell being completely full. 

 

5.)  As magnesium needs to lose two electrons and Chlorine would like to gain one. Therefore, the 2 Chlorine atoms will react with one Magnesium atom to form MgCl2. 

 

 

Answer 2

Have you learned this thing yet...

1s²2s²2p⁶3s²3p⁶4s²3d¹⁰ ...

 

This is the order in which electrons get filled. The big number in front represents the energy level.

The exponent represents how many electrons fit into each place.

Mg has 12 electrons so.

1s²2s²2p⁶3s²

2+2+6+2 = 12

The highest energy level is 3, and there are 2 electrons in that energy level.

This can also be seen if you have a picture of it. The outer most electrons are the highest energy level.

 

Cl has 17 electrons

1s²2s²2p⁶3s²3p⁵

2+2+6+2+5 = 17

Highest energy level is 3 and there are 7 electrons in that energy level.

To make 8, Cl needs to take 1 more electron.

As Mg has 2 electrons. To make 8, Mg would need to gain 6 more electrons. OR Mg can give away 2 electrons and go down an energy level. Giving away 2 electrons is easier.

 

So Mg gives away 2, and each Cl atom gains 1. 1 atom of Mg pairs with 2 atoms of Cl
MgCl₂

 

 

If you look at the periodic table, the 2 first columns usually give away electrons.

The 2nd to the last column(F,Cl,Br...) gains electrons. This give and gain pair is called ionic bonding.