Structure Of The Atom (Page 4 of 4) in pdf

CHEMISTRY

Chemistry extended writing 1

When answering extended writing questions you should try to:

✓

Apply your scienti c knowledge.

✓

Present your answer in a logical and organised way.

✓

Write full sentences and make sure that your spelling, punctuation and grammar

are as good as you can make them.

Fluorine has a mass number of 19 and an atomic number of 9.

Describe the numbers and arrangements of the protons, neutrons and electrons in an atom of ﬂ uorine.

(6 marks)

Sample answer 1

The atomic number is the number of protons and the mass number is the number of

neutrons and they are in the middle of the atom and the electrons are around the outside.

This is a basic answer. Most of the facts given are correct, although this student does

not remember what the mass number means. This answer could be improved by saying

how many protons, neutrons and electrons the atom has, and more about how they are

arranged. This student also needs to use correct scienti c words (such as nucleus and

electron shells), and to write in shorter sentences.

Sample answer 2

The atomic number shows that uorine has 9 protons in the nucleus. The mass number

is the total number of protons and neutrons, so uorine has 10 neutrons. These are also

in the nucleus.

An atom always has the same number of protons and electrons, so a uorine atom has

9 electrons. These are arranged in shells around the nucleus. The rst shell holds 2

electrons and the second one can hold up to 8. There are only 7 electrons left after two

of them have gone into the rst shell, so the electronic con guration of uorine is 2.7.

This is an excellent, detailed answer. As well as giving all the details about the structure

of the atom and the numbers of different particles, this answer also uses scienti c

words and phrases correctly (such as ‘electronic con guration’). It is also written in

sentences and paragraphs with correct spelling and grammar.

1. The electronic conﬁ guration of calcium is 2.8.8.2. The electronic conﬁ guration of oxygen is 2.6.

Explain what these conﬁ gurations tell you about atoms of these elements and how they will react

(6 marks)

together.

Structure Of The Atom Page 4