Question

What is the mass number of the isotope lithium-7?

Answer 1

Answer:

5 neutrons  are in the isotope lithium-8

Explanation:

In the periodic table, lithium being the third element, its atomic number will be 3. i.e. it has 3 protons.  

The atomic number = proton number

i.e. 3,

again we know that Mass number - proton number = neutron number.

In the given case it is, 8-3=5

In isotope 8 mass number will be 8, so as in isotope 7 it will be 7.

being a 3rd element in the periodic table its K shell contains 2 electron and L shell has 1 electron.

Answer 2

Answer:

What is the mass number of the isotope lithium-7

7

Lithium has 3 protons. How many neutrons are in the isotope lithium-8?

5