Question

Complete the following table

Isotope	Atomic #	Mass #	Protons	Neutrons	Electrons
26Mg2+			12
	34	81			36
		133		78	55

Answer 1

1) It seems given isotope = ²⁶Mg2+

Atomic number = 12

mass number = 26

Atomic number = protons or electrons

Protons =12

Since charge is +2 , Electrons = 12 -2 =10

Neutrons = Mass number - atomic number = 26-12 = 14

2) ⁸¹Se^2-

atomic number 34 = Se

Mass number = 81

Protons = 34

Neutrons = Mass number - atomic number = 81-34 = 47

Since electrons are 36, charge = 36- 34 = -2.

3) ¹³³Cs₅₅

Atomic number = 55

Mass number = 133

Atomic number = protons or electrons

Protons = 55

Neutrons = Mass number - atomic number = 133 - 78 = 55

Electrons = 55