The sum of the number of protons and number of neutrons is
called…………
NTS
PET ------2018 ETEA CT ------2019
a) Mass number
b) atomic number
c) Avogadro number
d) none of these
Atomic mass is denoted by…………….
a) A
b) Z
c) X
d) At
Atomic mass of aluminum is 27 and its atomic number is 13, find the number of protons and number of neutrons in aluminum?
NTS PST 15/12/2019 (11:30)
a) 13, 14
b) 14, 13
c) 12, 15
d) 15, 12
Solution: atomic number =13
no of proton = 13
we know that;
Mass number = no of protons + no of neutrons
27= 13 + n, 27 – 13 = n, n= 14
So protons =13, and neutrons = 14
Mass number of an atom represents:
NTS
PST –P-2----2015
a) sum of proton and electron
b) sum of proton and neutron
c) difference of neutron and proton
d) sum of electrons and neutrons
The combining capacity of the atoms to form molecules either with same or different elements is known as…………
a) joining
b) valiancy
c) combination
d) none of these
Atomic number of magnesium:
NTS PST 15/12/2019 (11:30), NTS CT 25/08/2019 (11:30)
a) 11
b) 12
c) 13
d) 14
