A substance that is made of only one sort of atom is called an element.
There are about 100 different elements.
Elements are shown in the periodic table.
Metals on the left side of the table and the non-metals are on the right side.
The groups contain elements with similar properties.
b) Atoms of each element are represented by a chemical symbol,
eg O represents an atom of oxygen, and Na represents an atom of sodium and others
c) Atoms have a small central nucleus, which is made up of protons and neutrons and around which there are electrons which move in specific energy levels (a sort of orbit, often called a shell) in the majority of the space of an atom.
d) Know their relative electrical charges i.e. proton is +1 and neutron 0 and the electron –1
1 of 2
C1.1 Fundamental ideas
e) In a neutral atom, the number of electrons is equal to the number of protons in the nucleus.
Therefore atoms have no overall electrical charge ie overall neutral (+ balances -).
Removing electrons from atoms makes positive ions.
Adding electrons to atoms makes negative ions.
f) All atoms of a particular element have the same number of protons.
Atoms of different elements have different numbers of protons.
Elements consist of one type of atom only.
g) The number of protons in an atom of an element is its atomic number.
The sum of the protons and neutrons in an atom is its mass number.
h) Electrons occupy particular energy levels.
Each electron in an atom is at a particular energy level (in a particular shell).
The electrons in an atom occupy the lowest available energy levels (innermost available shells).
Comments
No comments have yet been made