1. Moving from left to right

• A decrease in metallic properties
• An increase in non-metallic properties
• Change of the properties of oxides from basic to acidic
• A decrease in electrical conductivity of the element
• An increases in proton number

2. Proton number: number of protons in the nucleus of an atom

3. Electron arrangements of the elements

• For neutral atom, the number of protons is equal to the number of electrons
• The electrons are arranged in shells around the nucleus
• First shell: 2 electrons
• Second shell: 8 electrons
• Third shell: 18 electrons

4. Formation of positive and negative ions

• Some atoms will accept or donate electrons to form a stable electron arrangement
• Neutral atoms achieve a stable duplet or octet electron arrangement
• Positive ions: formed when the atoms of metal elements donate electrons
• Negative ions: formed when the atoms of non-metallic elements accept electrons

1. Moving from left to right

• A decrease in metallic properties
• An increase in non-metallic properties
• Change of the properties of oxides from basic to acidic
• A decrease in electrical conductivity of the element
• An increases in proton number

2. Proton number: number of protons in the nucleus of an atom

3. Electron arrangements of the elements

• For neutral atom, the number of protons is equal to the number of electrons
• The electrons are arranged in shells around the nucleus
• First shell: 2 electrons
• Second shell: 8 electrons
• Third shell: 18 electrons

4. Formation of positive and negative ions

• Some atoms will accept or donate electrons to form a stable electron arrangement
• Neutral atoms achieve a stable duplet or octet electron arrangement
• Positive ions: formed when the atoms of metal elements donate electrons
• Negative ions: formed when the atoms of non-metallic elements accept electrons