NCERT Based Test: Electronic Configurations & Types of Elements; s, p,

(A) Z = 62; 4f⁶ 5d° 6s² (f-block)
(B) Z = 47; 4d¹⁰ 5s¹ (d-block)
(C) Z=56; 6s² (s-block)
(D) Z = 53 ; 5s² 5p⁵ (p-block)

Atomic numbers of elements:

• Z = 3: Configuration is 1s² 2s¹.
• Z = 20: Configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².

Both elements belong to the s-block of the periodic table.

Element with atomic number 30 ; [Ar] 3d¹⁰ 4s²
Element with atomic number 48 ; [Kr] 4d¹⁰ 5s²
Element with atomic number 80; [Xe] 4f¹⁴5d¹⁰6s²

n = 4 hence, element lies in 4^th period.
Group number = ns + (n - 1)d = 2 + 8 =10

There are 18 groups and 7 periods in periodic table. All members of 18^th group are noble gases and first group contains alkali metals which are the most electropositive.

Barium belongs to s-block with an outer configuration 6s².

Correct answer: B

• Option A: Total electrons = 9, corresponding to Fluorine, which is the most electronegative element. This match is correct.

• Option B: Total electrons = 7, corresponding to Nitrogen, which is in period 2 and in group 15 (older notation: group V). The statement that it belongs to the 3rd period is incorrect. Therefore this match is wrong.

• Option C: Total electrons = 28, corresponding to Nickel, which is indeed a d-block element. This match is correct.

• Option D: Total electrons = 18, corresponding to Argon, a noble gas in group 18. This match is correct.

Final answer: B is the incorrect match because the element with seven electrons is in period 2, not in the 3rd period.

ns² np² are members of carbon family.
Chalcogens is the general name of 16^th group elements.

It belongs to p-block while other elements belong to d-block and same group.

For f-orbital, l = 3, m_l= 2l + 1 = 7
There are 7 electrons with +1/2 spin and 7 electrons with -1/2 spin. Hence, total electrons are 14.

Metalloids are shown by the zig-zag boxes and the elements preseht on the right side of the boundary are non-metals. Metals are present on the left side of the periodic table.

C is the wrong statement.

There are four transition series corresponding to the 3d, 4d, 5d and 6d blocks; each series ideally contains 10 elements.

Fluorine is the most electronegative element, so option A is correct.

Scandium (Sc) has electronic configuration [Ar] 3d1 4s2, is the first d-block (transition) element and lies in the fourth period, so option B is correct.

Within a period the halogens generally have the most negative electron gain enthalpy (largest tendency to gain an electron), so option D is correct.