Answer:
![(3)/(2)He](https://img.qammunity.org/2022/formulas/chemistry/college/t8d1vojpt7zksqnm09nfg3x4vnlfr4sypc.png)
![(6)/(2) He](https://img.qammunity.org/2022/formulas/chemistry/college/j3vd4806jxgst70y02med0d4klunx0mpb7.png)
![(7)/(4)Be](https://img.qammunity.org/2022/formulas/chemistry/college/ii07s5mtdmtndg0cvo4xk2je4och38c1re.png)
![(3)/(1) H](https://img.qammunity.org/2022/formulas/chemistry/college/n2fsnrts90j28j3k1ztclndrp313lstf1n.png)
![(6)/(4)Be](https://img.qammunity.org/2022/formulas/chemistry/college/7nvcpb860czf0n5pakna8x6avtdf51274w.png)
![(7)/(3) Li](https://img.qammunity.org/2022/formulas/chemistry/college/dbpthae9uipkgr95hdtshdj6ci9hma2k3l.png)
Step-by-step explanation:
In the first nucleus we are told that there are two protons and one neutron. Let us remember that the mass number = number of protons + number of neutrons.
This implies that, for the first specie the mass number is 3, for the second specie the mass number is 6 and the third specie has a mass number of 7 and so on. The mass number is indicated as a superscript.
The atomic number is the number of protons in the nucleus of the atom and helps us to identify the atom. It is always written as a subscript as shown.