Lesson 1.3 - Elements
In this lesson:
Elements
An element is a type of atom.
It is determined by the number of protons the atom has.
Elements are represented by different symbols.
Element symbols
Each elements has a unique symbol.
These symbols identify an element in a chemical reaction.
Some elements have 1-letter symbols (e.g. O for oxygen). Some have 2-letter symbols (e.g. He for helium).
Common element symbols
As of this document, there are 118 elements.
Below are some common ones:
O
Oxygen
N
Nitrogen
Si
Silicon
Na
Sodium
Mg
Magnesium
Og
Oganesson
H
Hydrogen
He
Helium
Li
Lithium
Periodic table
The elements can all be found on the periodic table.
It shows the electron configuration, the relative atomic mass, the state of matter, the number of protons, etc.
It's very useful :)
Common elements
The first 20 elements are listed below:
Hydrogen (H)
Helium (He)
Lithium (Li)
Beryllium (Be)
Boron (B)
Carbon (C)
Nitrogen (N)
Oxygen (O)
Fluorine (F)
Neon (Ne)
Sodium (Na)
Magnesium (Mg)
Aluminium (Al)
Silicon (Si)
Phosphorus (P)
Sulphur (S)
Chlorine (Cl)
Argon (Ar)
Potassium (K)
Calcium (Ca)
Group 1
Group 1 elements include:
2
Li
Lithium
3
7
3
Na
Sodium
11
23
4
K
Potassium
19
39
5
Rb
Rubidium
27
85.5
6
Cs
Caesium
55
133
7
Fr
Francium
87
223
These elements are called the alkali metals.
Group 7
2
F
Fluorine
9
19
3
Cl
Chlorine
17
35.5
4
Br
Bromine
35
80
5
I
Iodine
53
127
6
At
Astatine
85
210
7
Ts
Tennessine
117
294
These are the halogens, and are non-metals.
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