Some boron atoms have mass number 10 and some have mass number 11. These boron atoms with different mass numbers are called_____

Q.

Complete the following statements :

(a) Magnesium has 2 valence electrons in the ___ shell.

(b) The valency of nitrogen in $N_2$ molecule is ___

(c) Isotopes have different mass numbers because their nuclei contain different number of ___

(d) Some boron atoms have mass number 10 and some have mass number 11. These boron atoms with different mass numbers are called ___

Q. Complete the following statements :

(a) Magnesium has 2 valence electrons in the ............. shell.

(b) The valency of nitrogen in N₂ molecule is .............

(c) Isotopes have different mass numbers because their nuclei contain different number of .............

(d) Some boron atoms have mass number 10 and some have mass number 11. These boron atoms with different mass numbers are called .............

Q.

Some carbon atoms have mass number 12 and some have mass number 14. These atoms of same element of different mass numbers are called __.

Q. Atoms having the same mass number but different atomic number are called:

Q. Atoms having the same atomic number but a different mass number are called ___.