1.) if a neutral atom of chlorine has 17 electrons and 18 neutrons, how many electrons are in the second energy shell of this atom? 2.) if a neutral atom of chlorine has 17 electrons and 18 neutrons, how many electrons are in the outermost, or valence, shell of this atom?

1. 8 electrons

2. 7 electrons

Explanation: energy shell are orbits which Carry's electrons around an atom's nucleus.

To determine the number of electrons in an energy shell, use the formula

2(n^2)

n= number of energy shell

Therefore the second energy shell is n=2

Substituting n in the equation above,

2(2^2)=8

2. Valence electrons are the electrons on the outermost shell of an atomic nucleus.

The group number of an element is the same as the valence electrons of that element.

Therefore chlorine which belongs to group 7 elements has 7 valence electron.

We can also get the valence electrons using the K L M N shell.

The K shell which has maximum of 2 electrons, while other shells can contain maximum of 8 electron.

SEE PICTURE ATTACHED TO UNDERSTAND THE K L M N SHELL BETTER.

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2