s- and p-Block Elements MCQs for MDCAT with Answers – Page 2

The first ionisation energy of sulphur is lower than that of phosphorus mainly because ____.

Correct answer C. sulphur has one pair of electrons in a 3p orbital, and their mutual repulsion makes one easier to remove

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Question 22 s- and p-Block Elements

Which element is the most electronegative on the Pauling scale?

Correct answer B. Fluorine

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Question 23 s- and p-Block Elements

Which halogen releases the most energy when a gaseous atom gains one electron?

Correct answer C. Chlorine

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Question 24 s- and p-Block Elements

An element has the configuration 3d¹⁰4s²4p³. To which block and group does it belong?

Correct answer D. p-block, group 15

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Question 25 s- and p-Block Elements

An element with the configuration 4f⁷6s² is placed in which block of the periodic table?

Correct answer C. f-block

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Question 26 s- and p-Block Elements

What are the products when sodium reacts with cold water?

Correct answer D. Sodium hydroxide and hydrogen

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Question 27 s- and p-Block Elements

What volume of hydrogen at STP is produced when 2.3 g of sodium reacts completely with excess water (Na = 23, molar volume = 22.4 dm³)?

Correct answer D. 1.12 dm³

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Question 28 s- and p-Block Elements

Which Group I metal forms mainly the normal oxide M₂O when burnt in excess oxygen?

Correct answer C. Lithium

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Question 29 s- and p-Block Elements

What mass of calcium hydroxide forms when 0.80 g of calcium reacts completely with water (Ca = 40, O = 16, H = 1)?

Correct answer B. 1.48 g

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Question 30 s- and p-Block Elements

The reactivity of Group I metals with water increases down the group mainly because ____.

Correct answer C. the first ionisation energy decreases, so the outer electron is lost more easily

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Question 31 s- and p-Block Elements

What is formed when magnesium is heated in steam?

Correct answer C. Magnesium oxide and hydrogen

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Question 32 s- and p-Block Elements

Which Group II metal reacts most vigorously with cold water?

Correct answer B. Barium

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Question 33 s- and p-Block Elements

Which Group II element does not react with water or steam under ordinary conditions?

Correct answer D. Beryllium

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Question 34 s- and p-Block Elements

Which element of period 3 has the highest first ionisation energy?

Correct answer B. Argon

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Question 35 s- and p-Block Elements

Why is the first ionisation energy of aluminium lower than that of magnesium?

Correct answer A. The electron removed from Al is in a 3p orbital, which is higher in energy and partly shielded by 3s electrons

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Question 36 s- and p-Block Elements

Which of the following isoelectronic species has the smallest radius?

Correct answer B. Al³⁺

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Question 37 s- and p-Block Elements

Moving from sodium to chlorine across period 3, the atomic radius ____.

Correct answer B. decreases because effective nuclear charge increases

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