Skip to content
Dabour HubLEARN · PRACTICE · EXPLORESign inStudent

4.6Chemistry 01. Materials And Their Structure

Ions are atoms that have gained or lost electrons to become charged — Cambridge Checkpoint Science 0893 Revision Notes & Topical Questions

5 min read 8 parts Lesson 6 of 11 1 quiz

📚 Cambridge Checkpoint Science 0893 Hub / Topical Revision
🩺
100% Curriculum Specification Match Lesson Doctor Verified
The only platform with 100% curriculum specification match and verified interactive question banks.
0%read
Lesson summary

4.6 Ions: atoms that have gained or lost electrons — CHECKPOINT - Lower Secondary Science 0893 notes: Describe how atoms become positive or negative ions by losing or gaining electrons and write the symbols and charges of ions.Stable atoms — atoms are more stable when the outermo…

  • Noble gases
  • Other elements
  • Metal atoms
  • Positive ion
  • Electrostatic force
  • Stable atoms — atoms are more stable when the outermost electron shell is full

Section 1 of 8Why atoms form ions

Stable atoms
  • Stable atoms atoms are more stable when the outermost electron shell is full.
Noble gases
  • Noble gases the Group 8 elements already have full outer shells, so they do not react to form compounds.
Other elements
  • Other elements they gain, lose or share electrons to fill their outer shells.

Section 2 of 8Ion

  • Ion
    • an atom that has gained or lost electrons and so has become charged.
    • Protons have a charge of +1 and electrons have a charge of -1.
    • An atom has no overall charge because its protons and electrons are equal in number.

Section 3 of 8Positive ions by losing electrons

Metal atoms
  • Metal atoms they lose electrons from the outermost shell to form positive ions.
Sodium
  • Sodium a sodium atom [2,8,1] loses one electron and becomes a sodium ion Na+ [2,8].
  • It has 11 protons and 10 electrons, so it has an overall charge of +1.
  • The next shell is now the outermost shell and it is full.

Section 4 of 8Negative ions by gaining electrons

Non-metal atoms
  • Non-metal atoms they gain electrons to fill the outermost shell and form negative ions.
Chlorine
  • Chlorine a chlorine atom [2,8,7] gains one electron and becomes a chloride ion Cl- [2,8,8].
  • It has 17 protons and 18 electrons, so it has an overall charge of -1.

Section 5 of 8Ions with a larger charge

AtomElectrons movedIon
Magnesium [2,8,2]Loses 2Mg2+ [2,8]
Oxygen [2,6]Gains 2O2- [2,8]
Lithium [2,1]Loses 1Li+ [2]
Fluorine [2,7]Gains 1F- [2,8]

Section 6 of 8Reactivity and ion formation

Reactivity and ion formation
Group 1
  • Group 1 potassium is the most reactive and lithium the least reactive.
  • Potassium's outer electron is furthest from the protons, so the electrostatic force is weaker and it is lost more easily.
Group 7
  • Group 7 fluorine is more reactive than chlorine.
  • Fluorine's outer shell is closer to the protons, so it attracts an extra electron more strongly.

Section 7 of 8Key terms

TermMeaning
IonA charged particle formed when an atom gains or loses electrons.
Positive ionAn ion formed when an atom loses electrons.
Negative ionAn ion formed when an atom gains electrons.
Noble gasGroup 8 element with a full outer shell that is unreactive.
Electrostatic forceForce of attraction between positive and negative charges.

Section 8 of 8Exam technique

1
An ion has the same number of protons and electrons — an ion has unequal numbers.
2
Gaining electrons gives a positive charge — gaining electrons gives a negative charge.
3
Losing electrons changes the number of protons — only electrons are lost or gained.
4
Only metals form ions — non-metals form negative ions.

Last updated: