IB Chemistry SL Structure 1 Models of the Particulate Nature of Matter Questions

$$\frac{(46\times7.98)+(47\times7.32)+(48\times73.99)+(49\times5.46)+(50\times5.25)}{100} =47.93$$

Answer must have two decimal places with a value from 47.90 to 48.00.
Award [2] for correct final answer.
Award [0] for 47.87, the data booklet value.

Protons: 22 AND Neutrons: 26 AND Electrons: 22

$1 \mathrm{~s}^{2} 2 \mathrm{~s}^{2} 2 \mathrm{p}^{6} 3 \mathrm{~s}^{2} 3 \mathrm{p}^{6} 3 \mathrm{~d}^{2}$

Atomic number: number of protons (in nucleus/atom);
Mass number:
(sum of) number of protons and neutrons (in nucleus/atom);
Isotopes of an element:
atoms of same element / atoms with same number of protons/atomic number/Z but different number of neutrons/mass number/ A;

Penalize once only use of the term element in the three definitions, for example, number of protons in an element or number of protons and neutrons in an element or element with the same atomic number but different mass number.

$\mathrm{Li}^{+}: 2 / 1 \mathrm{~s}^{2}$;
$B: 2,3 / 1 \mathrm{~s}^{2} 2 \mathrm{~s}^{2} 2 \mathrm{p}^{1}$;

correct mathematical expression set-up (e.g. $\left(\frac{x}{100}\right)(10)+\left[\frac{(100-x)}{(100)}\right](11)=10.81$ );
19 \%;

Marking guidance:

Award [2] for correct final answer.

Mass number

(A)

Number of

protons

Number of

electrons

Number of

neutrons

6

3

3

7

3

3

Marking guidance:

Award [1 max] for correct number of neutrons for both isotopes if numbers of protons or electrons is not given.
Award [1 max] for correct number of protons and electrons for both isotopes if number of neutrons is not given or if numbers of neutrons are incorrect.