NEET Classification of Elements and Periodicity in Properties — Set 18

Question 1

Which element has the electronic configuration $1s^2 2s^2 2p^6 3s^1$?

Accepted Answer

Total electrons = 11, corresponding to Na (period 3, group 1). Others: Mg (12 electrons), Al (13 electrons), Ne (10 electrons).

Question 2

Which of the following has the highest lattice energy among group 2 fluorides?

Accepted Answer

Lattice energy increases with smaller ionic radii (higher charge density). BeF₂ has the highest lattice energy in group 2 due to Be²⁺’s small size, compared to MgF₂, CaF₂, or SrF₂.

Question 3

Which element in group 15 has the highest tendency to form stable compounds in the +3 oxidation state?

Accepted Answer

The +3 oxidation state becomes more stable down group 15 due to the inert pair effect. Bi forms stable $\ce{BiCl3}$ (+3), more so than N, P, or As, where +5 is also common.

NEET Chemistry: Classification of Elements and Periodicity in Properties — Practice Set 18

Q1. Which element has the electronic configuration \(1s^2 2s^2 2p^6 3s^1\)?

Q2. Which of the following has the highest lattice energy among group 2 fluorides?

Q3. Which element in group 15 has the highest tendency to form stable compounds in the +3 oxidation state?

Q4. What is the general outer electronic configuration of d-block elements?

Q5. Which element in the fourth period has the highest electronegativity?

Q6. Which group 2 element forms a hydroxide with the lowest solubility in water?

Q7. Which of the following fluorides has the highest ionic character?

Q8. Which group 17 element has the highest electron affinity despite not having the most negative electron gain enthalpy?

Q9. Which element in group 16 has the most negative electron gain enthalpy?

Q10. Arrange the following elements in order of increasing metallic character: Si, P, S, Cl.