// FIELD GUIDE 08 — LEVEL L3 (GCSE / NATIONAL 5)
Bonding: three ways atoms stick together
Atoms bond because a full outer shell is stable and a half-empty one isn't. How they get there — give away, share, or pool — decides everything about the material they make.
// FIG. 01 — PICK A BOND TYPE
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// L3 — IONIC BONDING
A metal atom (few outer electrons) hands them to a non-metal atom (nearly full outer shell). Both end up with full shells, but now the metal is positively charged and the non-metal negative — opposite charges lock them together in a giant repeating lattice. That lattice is why ionic compounds (like salt) are hard, brittle, and have high melting points.
// L3 — COVALENT BONDING
Two non-metal atoms — neither wants to give electrons away — share a pair instead, and both count the shared pair toward their own full shell. This makes strong bonds within a molecule, but the molecules themselves are only weakly attracted to each other — which is why covalent substances like water and CO₂ often have low melting/boiling points.
// L3 — METALLIC BONDING
Metal atoms all release their outer electrons into a shared "sea" that drifts freely between positive metal ions. That mobile sea explains metals' signature properties: it carries electric current easily, it lets layers of ions slide past each other without breaking (so metals bend rather than shatter), and it conducts heat well.
// REFERENCES & FURTHER READING
Cross-check against your own exam board's specification (AQA, Edexcel, OCR, SQA).