Atomic structure and periodicity

Which statement is correct for the ion ₄⁹Be²⁺?

• The ion contains 15 subatomic particles in the nucleus.

• The ion contains more protons than neutrons in the nucleus.

• The ion has an electron arrangement of 2,2.

• Most of the total volume of the ion is empty space.

Which species has the electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁸ ?

• Ni

• Ni²⁺

• Fe

• Cu²⁺

How many electrons does the ion ₁₅³¹P^3- contain?

• 12

• 15

• 16

• 18

Bromine consists of two stable isotopes that exist in approximately a 1 : 1 ratio. The relative atomic mass, A_r, of bromine is 79.90. Which are the stable isotopes of bromine?

• ⁷⁹Br and ⁸¹Br

• ⁸⁰Br and ⁸¹Br

• ⁷⁸Br and ⁸⁰Br

• ⁷⁹Br and ⁸⁰Br

What is the order of increasing energy of the orbitals within a single energy level?

• d < s < f < p

• s < p < d < f

• p < s < f < d

• f < d < p < s

Ultraviolet radiation has a shorter wavelength than infrared radiation. How does the frequency and energy of ultraviolet radiation compare with infrared radiation?

• Frequency = higher; energy = higher

• Frequency = higher; energy = lower

• Frequency = lower; energy = higher

• Frequency = lower; energy = lower

The full electron configuration of an element is:

1s² 2s² 2p⁶ 3s² 3p²

To which group and period does the element belong?

• Group = 2 Period = 3

• Group = 13 Period = 2

• Group = 3 Period = 4

• Group = 14 Period = 3

Which transition in the hydrogen atom emits visible light?

• n = 1 to n = 2

• n = 2 to n = 3

• n = 2 to n = 1

• n = 3 to n = 2

Which statements are correct for the emission spectrum of hydrogen?

I. The lines converge at higher frequencies.

II. Electron transitions to n = 2 are responsible for lines in

the visible region.

III. Lines are produced when electrons move from lower to

higher energy levels.

• I and II only

• I and III only

• II and III only

• I, II and III

Element X is in group 15 and period 4 of the periodic table. Which statement is correct?

• X has 5 occupied energy levels.

• X can form ions with 3– charge.

• X is a transition element.

• X has 4 valence electrons.