atomic structure

Question 1

State two differences between the ‘plum pudding’ model and the model of atomic structure used today.

Answer 1

Assume current model unless otherwise stated.
Statement about the nucleus:
(Central) nucleus contains protons and neutrons.

Statement about electrons
Electrons are now arranged in energy levels/shells/orbitals

Question 2

why is na smaller than F in NaF

Answer 2

Both Na+ and F– same electron arrangement (1s22s22p6) or isoelectronic

Sodium (ion) has more protons so attracts (outer) electrons closer / Sodium (ion) has more protons so stronger attractions for (outer) electrons

Question 3

Explain how ions are detected and relative abundance is measured in a TOF mass spectrometer.

Answer 3

ion hits the detector / negative plate and gains an electron

Not positive plate
(relative) abundance is proportional to (the size of) the current

Question 4

Explain why the second ionisation energy of calcium is lower than the second ionisation energy of potassium

Answer 4

m1.  n Ca(+) (outer) electron(s) is further from nucleus
Or Ca(+) loses electron from a higher (energy) orbital
Or Ca(+) loses electron from a 4(s) orbital or 4th energy level or 4th energy shell and K(+) loses electron from a 3(p) orbital or 3rd energy level or 3rd energy shell

m2 More shielding (in Ca+)

Question 5

This question is about s-block metals.

(a) Give the full electron configuration for the calcium ion, Ca2+

Answer 5

1s2 2s2 2p6 3s2 3p6 (4s0)

Question 6

In the early twentieth century the apparatus shown in the diagram was used to investigate atomic structure. When He2+ particles were fired at a thin sheet of gold, most of the particles were detected at point P.

What conclusion can be drawn from the detection of He2+ particles at point P?

A
Gold atoms contain electrons.

B
Gold atoms contain protons.

C
Gold atoms contain neutrons.

D
Gold atoms are mainly empty space.

Answer 6

D

Question 7

When He2+ particles were fired at a thin sheet of gold, about 1 in 8000 of the particles were detected at point Q.

What conclusion can be drawn from the detection of He2+ particles at point Q?

A
Gold atoms have a small, positive nucleus.

B
Gold atoms have electrons in orbitals.

C
Gold consists of ions in a sea of delocalised electrons.

D
Gold atoms have more protons than He2+ particles.

Answer 7

A

Question 8

Write an equation, including state symbols, to represent the process that occurs when the third ionisation energy of manganese is measured.

Answer 8

Mn2+ (g) ⟶ Mn3+ (g) + e−

Question 9

State which of the elements magnesium and aluminium has the lower first ionisation energy.
Explain your answer.

Answer 9

Al
Mg then CE = 0

(Outer) electron in (3)p sublevel / orbital
Not just level or shell

Higher in energy / further from the nucleus
so easier to remove OWTTE