If Z is the number of protons and A the number of nucleons, then the number of neutrons in an atom is given by

If Z is the number of protons and A the number of nucleons, then the number of neutrons in an atom is given by

Multiple Choice Questions

(a) The outermost shell of an atom is known as

(i) valency

(ii) valence electrons

(iii) nucleus

(iv) valence shell

(b) The number of valence electrons present in magnesium is

(i) two

(ii) three

(iii) four

(iv) five

(c) The sub atomic particle with positive charge is

(i) proton

(ii) neutron

(iii) electron

(iv) nucleon

(d) If the atomic number of an atom is 17 and mass number is 35 then number of neutrons will be

(i) 35

(ii) 17

(iii) 18

(iv) 52

(e) The number of electrons in an atom is equal to the number of

(i) protons in a neutral atom

(ii) neutrons in a neutral atom

(iii) nucleons in a neutral atom

(iv) none of the above

(f) The sum of number of protons and number of neutrons present in the nucleus of an atom is called its

(i) mass number

(ii) atomic number

(iii) number of electrons

(iv) all of the above

The mass number of an atom is determined by the number of protons and neutrons. Calculate the mass number of a Sodium (Na) atom if the number of neutrons in it are 12.

If sodium has atomic number 11 and mass number of 23, then the number of protons, neutrons, and electrons in an uncharged atom is :