1. Complete the chart:

Symbol     #protons     #electrons     #neutrons     Mass #     At. #

Li

Na⁺¹

Cl

Rn-220

As

Sr ⁺²

S^-2

Ni
 
 

ANSWERS:

Symbol         #protons     #electrons     #neutrons     Mass #     At. #

Li                     3                 3                 4                 7             3

Na⁺¹                     11              10                12               23           11

Cl                    17               17                18               35           17

Rn-220            86               86               134             220         86

As                   33               33                42              75             33

Sr ⁺²                    38                36                50               88           38

S^-2                         16               18                16               32            16

Ni                    28               28                31               59            28