Answer:
A. Atomic number is 8, mass number of M is 16
B. Oxygen, O
C. 8 valence electrons, valency is 2
Explanation:
A. Atomic number = proton number
M2- = 2 extra electrons after forming octet structure, so 10-2=8
8 corresponds to number of protons, so atomic number is 8.
Mass number is number of protons + neutrons = 8+8=16
B. 8 in periodic table corresponds to oxygen
C. Number of valence electrons in an oxide ion is 8, valency is two as it forms -2 charge
