Skip to main content

Ions

Akoranga 5 Mahi Tuatahi


Ngā Whāinga Ako

  1. Can describe why ions form and identify the difference between cations & anions
  2. Locate groups 1, 2, 16, 17, 18 elements on the periodic table and identify their number of valence electrons
  3. Describe how ionic bonds are formed from the transfer of electrons

Write the date and ngā whāinga ako in your book


Ions

An atom or molecule that has gained or lost electrons, and has become charged.

Source



Tauria/Example: Sodium Fluoride

Source


Tauria/Example: Sodium Chloride

Source


Which Atoms Form Ions?

Open your periodic table an find groups 1, 2, 16 and 17

Highlight these columns and add a label saying they will form ions.


  1. Open to your ionic configuration diagrams
  2. Look at the valence shell of groups 1, 2, 16, 17 and 18
  3. Pātai: What do all the elements in each group have in common?
    • Elements in group 1 have 1 valence electron
    • Elements in group 2 have 2 valence electrons
    • Elements in group 18 have a full valence shell
    • Elements in group 17 are missing 1 electron
    • Elements in group 16 are missing 2 electrons

What is Special About Group 18?



Akoranga 7 Mahi Tuatahi

Work in pairs to answer these questions:

  1. What is the formula of the hydrogen ion?
  2. What is the formula of the oxide ion?
  3. What is the formula of the iron (II) ion?
  4. What is the name of the $OH^{-}$ ion?
  5. What is the name of the $Cl^{-}$ ion?

Ngā Whāinga Ako

  1. Be able to define cation and anion
  2. Be able to name ionic compounds

Write the date and ngā whāinga ako in your book


Cations

Cation: An atom that has lost electrons to become positively charged


Anions

Anion: An atom that has gained electrons to become negatively charged