What holds the atoms together in a covalent bond

In covalent bonding, both atoms are trying to attract electrons--the same electrons. Thus, the electrons are shared tightly between the atoms. The force of attraction that each atom exerts on the shared electrons is what holds the two atoms together.

the attraction between shared electrons and protons in each nucleus

Explanation:

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg