## Classification of Elements and Periodicity in Properties Questions and Answers Part-2

1. Which of the following remains unchanged on descending in a group in the periodic table?
a) Valence electrons
b) Atomic size
c) Density
d) Metallic character

Explanation: Valence electrons

2. Which is true about the electronegativity order of the following elements?
a) P > Si
b) C > N
c) Br > Cl
d) Sr > Ca

Explanation: P > Si

3. Electronic configuration of most electronegative element is
a) $1s^{2}2s^{2}2p^{4}3s^{1}$
b) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{5}$
c) $1s^{2}2s^{2}2p^{5}$
d) $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}$

Explanation: $1s^{2}2s^{2}2p^{5}$

4. Going from fluorine to chlorine, bromine and iodine, the electronegativity
a) increases
b) decreases
c) first decrease then increases
d) changes randomly

Explanation: Going from fluorine to chlorine, bromine and iodine, the electronegativity decreases

5. Which of the following is most electronegative?
b) Silicon
c) Carbon
d) Tin

Explanation: Carbon

6. On going from right to left in a period in the periodic table, the electronegativity of the elements
a) increases
b) decreases
c) remains unchanged
d) decreases first then increases

Explanation: On going from right to left in a period in the periodic table, the electronegativity of the elements decreases

7. The electronegativity follows the order
a) F > O > Cl > Br
b) F > Cl > Br > O
c) O > F > Cl > Br
d) Cl > F > O > Br

Explanation: F and O belong to 2nd period whereas Cl and Br belong to 3rd and 4th periods respectively. Hence the sequence of the E.N. is F > O > Cl > Br

8. Electronegativity values for the elements help in predicting
a) polarity of bonds
b) dipole moments
c) valency of elements
d) position in the electrochemical series

Explanation: Higher the value of electronegativity difference, more polar is the bond.

9. Which of the following is correctly matched?
a) C—C bond length — 0.077 nm
b) Ionic radius of Na+ — 0.136 nm
c) C—Cl bond length — 0.176 nm
d) Ionic radius of F- — 0.095 nm