The average atomic mass of the element is the weighted average atomic mass of element with respect to the natural abundance of all the isotopes.
isotopes are atoms of the same elements with different mass numbers , in other words same number of protons but different numbers of neutrons.
to find the average atomic mass we need to know the atomic masses of all the isotopes in addition to the natural abundance percentages of the isotopes.
answer is we need to know the atomic masses of the isotopes as well
X volume= 2x2x2=8
y volume= 8x8x8=512
512/8=64 so you can fit 64
Explanation:
The electronic configuration of sodium with Z = 11 is : 2, 8, 1
The electronic configuration of chlorine with Z = 17 is : 2, 8, 7
The Lewis structure is drawn in such a way that the octet of each atom is complete.
Thus, sodium losses one electron to chlorine and chlorine accepts this electron to form ionic bond.
Thus, the valence electrons are shown by dots in Lewis structure. The structure is shown in image below.
Answer: at relatively low temperatures.
Explanation:
According to Gibbs equation;

= Gibb's free energy change
= enthalpy change
T = temperature
= entropy change
A reaction is spontaneous when
= Gibb's free energy change is negative.
Thus 

Thus the reaction is spontaneous or
is negative only when 
Thus the reaction is spontaneous at relatively low temperatures