NEET Classification of Elements and Periodicity in Properties — Set 7

Question 1

Which element has the lowest first ionization enthalpy in the fifth period?

Accepted Answer

First ionization enthalpy decreases across a period from right to left. In period 5, Rb (group 1) has the lowest value compared to Sr, Ag, and I.

Question 2

Which element in group 2 has the highest hydration enthalpy due to its ionic size?

Accepted Answer

Hydration enthalpy increases with smaller ionic size and higher charge density. Be²⁺ (smallest in group 2) has the highest hydration enthalpy compared to Mg²⁺, Ca²⁺, or Sr²⁺.

Question 3

Which element in group 13 has the highest ionization enthalpy after losing two electrons?

Accepted Answer

Third ionization enthalpy is highest for B (removing an electron from $\ce{B^2+}$ with $1s^2$) due to its small size and stable configuration, compared to Al, Ga, or In.

NEET Chemistry: Classification of Elements and Periodicity in Properties — Practice Set 7

Q1. Which element has the lowest first ionization enthalpy in the fifth period?

Q2. Which element in group 2 has the highest hydration enthalpy due to its ionic size?

Q3. Which element in group 13 has the highest ionization enthalpy after losing two electrons?

Q4. What is the general outer electronic configuration of group 17 elements?

Q5. What is the formula of the compound formed by magnesium and nitrogen?

Q6. Arrange the following elements in order of increasing covalent radius: N, P, As, Sb.

Q7. Which of the following elements has the highest metallic character?

Q8. Which element forms a neutral oxide?

Q9. Arrange F, Cl, Br in order of decreasing electron gain enthalpy (most negative to least negative).

Q10. How many elements are present in the fourth period of the periodic table?