Chemistry, SS 1 Week 7
Topic: Elements and Symbols
The atoms are particles of elements and are represented by chemical symbols. A chemical symbol is a sign and it is made up of a letter or two letters to represent the atom of the element. Chemical symbols of atom of elements are derived from the names of the elements.
The following rules are used for deriving symbols:
- The first letter of the name is taken and this is written as a capital letter e.g. C for Carbon.
- The first and the second letters of the name is taken and first is written in capital letter while the second is in small letter e.g. Ca for Calcium, Al for Aluminium.
- Some first and the third letters of the name is taken and the first is written in capital letter while the third is in small letter e.g. Mg for Magnesium
- Some elements have Latin names, the symbols are derived from the Latin names e.g. The symbol for copper is Cu from Latin name is cuprum
A list of some elements is shown below:
|
Element |
Symbol |
Atomic Number |
Atomic Mass |
Number of Protons |
Number of Neutrons |
|
Hydrogen |
H |
1 |
1 |
1 |
0 |
|
Helium |
He |
2 |
4 |
2 |
2 |
|
Lithium |
Li |
3 |
7 |
3 |
4 |
|
Beryllium |
Be |
4 |
9 |
4 |
9 |
|
Boron |
B |
5 |
11 |
5 |
6 |
|
Carbon |
C |
6 |
12 |
6 |
6 |
|
Nitrogen |
N |
7 |
14 |
7 |
7 |
|
Oxygen |
O |
8 |
16 |
8 |
8 |
|
Fluorine |
F |
9 |
18 |
9 |
9 |
|
Neon |
Ne |
10 |
20 |
10 |
20 |
|
Sodium |
Na |
11 |
23 |
11 |
12 |
|
Magnesium |
Mg |
12 |
24 |
12 |
12 |
|
Aluminum |
Al |
13 |
27 |
13 |
14 |
|
Silicon |
Si |
14 |
28 |
14 |
14 |
|
Phosphorous |
P |
15 |
31 |
15 |
16 |
|
Sulphur |
S |
16 |
32 |
16 |
16 |
|
Chlorine |
Cl |
17 |
35 |
17 |
16 |
|
Argon |
Ar |
18 |
40 |
18 |
22 |
|
Potassium |
K |
19 |
39 |
19 |
20 |
|
Calcium |
Ca |
20 |
40 |
20 |
20 |
Iron Fe 26 56 2630
Copper Cu 29 63.5 2934.5
Zinc Zn 30 65.5 3035.5
Valency
Valency is defined as the combining power of any element. Valence describes how easily an atom or radical can combine with other chemical species. This is determined based on the number of electrons that would be added, lost or share if it reacts with other atoms. Valence is denoted using a positive or negative integer used to represent this binding capacity. For example, common valences of copper are 1 and 2.
Table of Element Valencies
|
Number |
Element |
Valency |
|
1 |
Hydrogen |
1 |
|
2 |
Helium |
0 |
|
3 |
Lithium |
1 |
|
4 |
Beryllium |
2 |
|
5 |
Boron |
3 |
|
6 |
Carbon |
2 and 4 |
|
7 |
Nitrogen |
3 and 5 |
|
8 |
Oxygen |
2 |
|
9 |
Fluorine |
1 |
|
10 |
Neon |
0 |
|
11 |
Sodium |
1 |
|
12 |
Magnesium |
2 |
|
13 |
Aluminum |
3 |
|
14 |
Silicon |
4 |
|
15 |
Phosphorus |
3 and 5 |
|
16 |
Sulphur |
2, 4 and 6 |
|
17 |
Chlorine |
1 |
|
18 |
Argon |
0 |
|
19 |
Potassium |
1 |
|
20 |
Calcium |
2 |
|
21 |
Scandium |
3 |
|
22 |
Titanium |
2 and 4 |
|
23 |
Vanadium |
3 and 5 |
|
24 |
