Question 1

Which of the following statements best explains why the atomic radius of transition metals does not decrease as much across a period compared to main group elements?

Accepted Answer

The number of outermost electrons remains constant, reducing the effect of increased nuclear charge.

Question 2

What is the primary cause of the lanthanide contraction observed in period 6 transition metals?

Accepted Answer

Increase in effective nuclear charge ($$Z_{\mathrm{eff}}) $$due to filled 4f subshell.

Question 3

Which element from each pair would you predict to have the largest atomic radius?

Accepted Answer

Ni & Ti: Ti

Question 4

Why do period 5 and period 6 transition metals have similar atomic radii despite the increase in principal quantum number?

Accepted Answer

Lanthanide contraction increases $$Z_{\mathrm{eff}}$$, pulling electrons closer.

Question 5

Which of the following transition metals would you expect to be larger but are actually the same or nearly the same size as Tc (technetium)?

Accepted Answer

Mo

Question 6

Across a period, the number of outermost electrons in transition metals is:

Accepted Answer

Constant

Question 7

Which trend is observed in the atomic radius of main group elements as you move from left to right across a period?

Accepted Answer

Atomic radius decreases

Question 8

What effect does an increase in electrons in the same shell have on the attractive force experienced by those electrons?

Accepted Answer

It decreases the attractive force due to increased electron-electron repulsion.

Question 9

Which of the following best describes the atomic radius trend for transition metals as you move down a group from period 5 to period 6?

Accepted Answer

Atomic radius remains relatively constant due to lanthanide contraction.

Question 10

If the effective nuclear charge ($$Z_{\mathrm{eff}}) $$increases, what happens to the atomic radius?

Accepted Answer

Atomic radius decreases

Question 11

Which of the following is a direct consequence of the lanthanide contraction in transition metals?

Accepted Answer

Period 6 transition metals have smaller than expected atomic radii.

Question 12

Which element would you expect to have a larger atomic radius: Y (yttrium) or Ag (silver)?

Accepted Answer

Y (yttrium)

Question 13

Which of the following is NOT a reason for the relatively small change in atomic radius across a period for transition metals?

Accepted Answer

Loss of electrons from the nucleus

Question 14

Which of the following best explains why the atomic radius of La (lanthanum) and Hf (hafnium) are nearly the same?

Accepted Answer

Lanthanide contraction causes Hf to have a smaller radius than expected.

Question 15

Which of the following elements has the smallest atomic radius among the period 5 transition metals listed: Zr, Nb, Mo, Tc, Ru?

Accepted Answer

Ru

Question 16

A chemist is comparing the atomic radii of Mn and Fe. Which element is expected to have a smaller atomic radius and why?

Accepted Answer

Fe, because it has a higher effective nuclear charge ($$Z_{\mathrm{eff}})$$

Question 17

Which of the following statements about the atomic radius of transition metals is correct?

Accepted Answer

Atomic radius decreases slightly across a period due to increasing $$Z_{\mathrm{eff}}.$$

Question 18

Which of the following elements would you expect to have the largest atomic radius: La, Hf, Ta, W?

Accepted Answer

La

Question 19

If a transition metal has a filled subshell, what effect does this have on its effective nuclear charge ($$Z_{\mathrm{eff}}$$)?

Accepted Answer

It increases $$Z_{\mathrm{eff}}$$ due to poor shielding by the filled subshell.

Question 20

Which of the following is a result of the lanthanide contraction in the context of transition metals?

Accepted Answer

Period 6 transition metals are nearly the same size as period 5 transition metals.

Atomic Radius and Density of Transition Metals

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