Jawaban:

1.⁴⁰Ca= no massa=40

²⁰ no atom =20

lambang unsur= Ca

jml Proton= no atom=20

jml elektron= no atom=20

jml neutron= no massa-no atom

=40-20=20

2.⁸⁴Kr= no massa=84

³⁶ no atom=36

lambang unsur=Kr

jml Proton= no atom=36

jml elektron= no atom=36

jml neutron= 84-36=40

3.⁸⁰Br= no massa=80

³⁵ no atom=35

lambang unsur=Br

jml Proton=35

jml elektron=35

jml neutron=80-35=45

4.⁵⁹Co= no massa=59

²⁷ no atom=27

lambang unsur=Co

jml Proton=27

jml elektron=27

jml neutron=59-27=32

5.²⁴Na= no massa=24

¹¹ no atom=11

jml Proton=11

jml elektron=11

jml neutron=24-11=13

Penjelasan:

semoga membantu:)