Zusammenfassung der Ressource
C1.1.1 Atoms + C.1.1.2 The periodic table
- All substances are made up of atoms
- Element
- A substance that is made up of only one type of atom
- There are about 100 different elements
- Which are shown in the periodic table, grouped into similar properties (a 'group' is
one vertical column)
- They are also shown as metals...
- ...and non-metals
- Grouped in the periodic table
- C1.1.2 The periodic table
- Elements in the same group have the same no. of electrons in their outer shells
- Giving them similar properties
- The elements in Group 0 are called the noble gases
- They are unreactive- their atoms have a stable arrangement of electrons
- Each element is
represented by a
chemical symbol
e.g O for Oxygen,
Na for Sodium etc..
- (These will be given to you in the exam)
- An atom has a small central nucleus, made up of protons and neutrons
- Around which there are sub-atomic particles called electrons
- Relative charges:
Protons: +1.
Neutron: 0.
Electron: -1.
- In an atom, no. of protons = no. of electrons
- Meaning atoms have no overall charge
- All atoms of a particular element have the same number of electrons
- and atoms of different elements have different numbers of protons
- Atomic number
- The number of protons in an atom of an element
- Mass number
- The sum of the protons and neutrons in an atom
- Electrons
- ... each occupy particular energy levels (or 'shells')
- They occupy the lowest available energy level (innermost available shells)
- The first 3 innermost shells fill up as: 2, 8, 8