Write the atomic number of the element present in the third period and seventeenth group of the periodic table.

Answer : The element with atomic number 12 has same chemical properties as that of calcium. This is because both of them have same number of valence electrons (2).

Number of electrons (Z = 5) = 5 Number of protons (Z = 5) = 5 Number of neutrons (A = Z) = 11 – 5 = 6 Since the atomic number is...

Valency is zero as K shell is completely filled

Electronic configuration : 2, 8, 8, 2 (i) 'X'is in the 2nd group and 4th period of the periodic table. (ii) X    +     Y----->     XY   2,8,8,2    2,6 (iii) The nature...

Electronic configuration of Q : 2, 8, 3 Valency of Q: 3 Electronic configuration of R: 2, 8, 5 Valency of R: 8-5=3 P      +      S ----> PS 2,8,1     2,8,7

The properties of elements depend upon valence electrons in the atom which in turn depends on the total number of electrons, i.e., atomic number. Therefore, atomic number is a more appropriate parameter...

(i) Y (ii) 2 each (ii) False, same period but Y lies in group 2 and X in group 16. So, as we mover from left to right size decreases with increase in...

Mendeleev’s Periodic Table Modern Periodic Table Mendeleev's periodic table is based on atomic mass. Elements are arranged in increasing order of their atomic masses. Modern periodic table is based on atomic number. Elements are arranged...

Mendeleev’s periodic table                                      Modern periodic table.                ...

(i) Electronic configuration – 2,8,2  (ii) Metal, as it can easily lose electrons (from outer most orbit)  (iii)      (a) X    Y                 ...