No such substance as 'NaCl2'. However, NaCl (sodium chloride or common table salt) has two atoms viz. 1 x sodium(Na) and 1 x chlorine(Cl).
2
All atoms of one kind share common properties
Covalent bonds are the type of bonds that occur when atoms share electrons.
the atoms share electrons
If the atoms in a covalent bond share electrons equally, the bond is nonpolar.
This question seems a bit unclear. Perhaps it meant something like: "how many electrons can be shared with carbon atoms?" Anyway, a carbon atom can share 4 electrons with other atoms, including other carbon atoms.
I know that table salt has no hydrogen atoms; NaCl2
a carbon atom can share electrons with up to four other atoms.
NaCl2 does not exist. Perhaps you are referring to NaCl, in which case the cation is Na^+.
Covalent bonds are formed when atoms share electrons
All atoms of one kind share common properties
electrons share ionic bond between atoms. Covalent bond may also be present.
Atoms share electrons when they form covalent bonds.
A covalent bond forms when atoms share electrons.
hydrogen atoms share electrons when it forms covalent bonds
It mean something
two electrons
covalent bond (There is also metallic bonding, which is many, many atoms sharing an electron, not just neighboring electrons.)