Answer:
C) Potassium, K, and calcium, Ca
Explanation:
Given pair of elements:
Ni and Cu
Potassium and Ca
Nitrogen and oxygen
Solution:
We know that number of protons and number of electrons are always equal and number of electron or number of proton is called atomic number.
Number of protons given elements:
Ni number of protons = 28
Copper number of protons = 29
Combine number of protons = 57
K number of protons = 19
Ca number of protons = 20
Combine number of protons = 39
Ni number of protons = 7
O number of protons = 8
Combine number of protons = 15
Thus, option C is correct.
