Metals, non-metals, metalloids — properties: Foundations

Before you can reason your way through the parent note, you need a toolbox of tiny ideas — each one a plain word attached to a picture. We build them in order, so no symbol ever appears before it has been earned. Start reading from line one; nothing below assumes you already know it.

1. The atom = nucleus + electron shells

The picture. Think of a bee-hive: the queen (nucleus) at the centre, worker bees (electrons) buzzing in rings around her. Opposite charges attract, so the positive nucleus pulls the negative electrons inward — like invisible elastic threads.

Figure — Metals, non-metals, metalloids — properties

Why the topic needs it. The whole parent note is about whether an atom lets go of an electron or grabs one. You cannot talk about letting go until you can see the thing being held (electron) and the thing holding it (nucleus).

2. Positive, negative, and "charge"

The picture. Two magnets: north–north push away, north–south snap together. Charges behave the same way. The symbol $+$ just means "the pulling-partner of $-$ ."

Why the topic needs it. When a metal "loses an electron" it keeps more $+$ than $-$ , so overall it becomes a positive ion (next section). "Basic oxide," "cation," "sea of electrons" — all of it is charge bookkeeping.

3. Ions: what "losing" or "gaining" an electron makes

The picture. Start balanced: 11 pluses in the nucleus, 11 minuses buzzing → net zero. Flick away one electron → 11 pluses, 10 minuses → net $+ 1$ . That leftover imbalance is the cation.

Why the topic needs it. "Metals form $+$ ions / basic oxides" and "non-metals form $-$ ions / acidic oxides" are stated as facts in the parent. Now you can derive them: metal loses → cation → its oxide reacts with water to give a base.

4. Valence electrons: the ones that actually matter

The picture. In our bee-hive of rings, only the outer ring bees are close to escaping; the inner-ring bees are trapped near the queen. Chemistry happens at the edge.

Why the topic needs it. "Na loses its one 3s electron," "carbon uses 3 of its 4 valence electrons" — these lines in the parent are all about valence electrons. To count them properly you'll lean on Electronic Configuration.

5. The periodic table's map: groups and periods

The picture. Think of a bookshelf. A period is a single shelf you slide along sideways; a group is one vertical stack of books lined up above each other. "Down a group" = go down a column; "across a period" = go along a row.

Why the topic needs it. Every trend rule in the parent is phrased as a direction on this grid — "across a period → IE ↑," "down a group → radius ↑." You literally cannot read those rules until you know which way is a row and which is a column.

6. Shielding and radius: why the grip weakens

The picture. Two ideas, one message: distance and umbrellas both weaken the pull.

Farther electron (big radius) → weaker attraction (pull fades with distance).
More inner electrons (more shielding) → weaker attraction (umbrella thicker).

Why the topic needs it. The parent says "down a group → radius ↑, shielding ↑ → electron held looser." You now see why: the outer bee is farther out and better shaded, so it escapes easily. See Periodic Trends — Atomic Radius.

7. The proportional sign " $\propto$ " — reading a trend

The picture. A see-saw. In $A \propto \frac{1}{B}$ , when one seat goes down, the other seat goes up. That single see-saw is how we'll read the metallic-character trend in the next sections.

Why the topic needs it. Every "↑ / ↓" arrow in the parent's trend rules is a $\propto$ statement in disguise. Once you can read a see-saw, you can chain them: radius ↑ ⇒ IE ↓ ⇒ metallic character ↑. We define this before using it below.

8. Metallic character: what the word actually means

The picture. A slider from 0 to 10. At the metallic end (10): a shiny, bendable copper wire humming with current. At the non-metallic end (0): a dull, brittle lump of sulfur that won't conduct. Every element sits somewhere on this slider.

Why the topic needs it. The parent's master rule links this slider to ionisation energy. You need to know the slider measures real properties — not a vague vibe — before you can trust the link in §9.

9. Ionisation energy (IE): the price tag on losing an electron

The picture. A balloon on a string. A loose grip (metal) = the balloon tugs free with a light pull (low IE). A death-grip (non-metal) = you must yank hard (high IE).

Why this tool and not another? We could describe "willingness to lose an electron" in vague words, but IE turns it into a number you can compare and rank. That's why Example 2 in the parent can order Na > Mg > Al with no data table — just the direction IE changes across a period. Full detail: Ionisation Energy.

10. Electronegativity: the mirror concept

The picture. Two kids sharing a rope (a shared electron pair). The greedier kid (higher electronegativity) drags the rope to their side. Fluorine is the greediest kid on the table.

Why the topic needs it. IE explains metals (easy to lose); electronegativity explains non-metals (eager to grab). They are two ends of the same tug-of-war. See Electronegativity.

11. Reading chemical formulas and reaction arrows

Before the chemistry payoff we need to read the shorthand chemists write.

The picture. A recipe card: ingredients on the left of the arrow, finished dish on the right. Subscripts are just "how many of each ingredient."

Why the topic needs it. Section 12 and the parent's worked examples are written entirely in this shorthand ( $Na_{2} O + H_{2} O \to NaOH$ ). Now you can read every one.

The nucleus — positively charged.

Where do electrons live and what charge do they carry?

In shells around the nucleus — negatively charged.

Do same charges push or pull?

Push apart (repel); opposite charges pull together.

An atom that loses an electron becomes a ___ with what charge?

A cation, net positive.

An atom that gains an electron becomes a ___ with what charge?

An anion, net negative.

Which electrons take part in chemistry?

The valence (outermost-shell) electrons.

On the periodic table, what is a period and what is a group?

A period is a horizontal row; a group is a vertical column.

Two things that weaken the nucleus's grip on the outer electron?

Bigger radius (distance) and more shielding (inner electrons blocking the pull).

What does

A \propto \frac{1}{B}

mean?

A goes up when B goes down (inverse relationship).

In plain traits, what does "metallic character" measure?

How metal-like an element is — conducts electricity and heat, shiny, bendable, loses electrons easily.

What is ionisation energy in plain words?

The energy needed to remove one electron from a neutral atom.

Metallic character is proportional to 1 over what?

Ionisation energy — lower IE means more metallic.

What does electronegativity measure?

How strongly an atom pulls shared electrons toward itself.

Na_{2} O

, what does the small "2" mean, and what does "→" mean?

The subscript 2 = two sodium atoms; the arrow means "reacts to turn into."

Metal oxide plus water gives a ___; non-metal oxide plus water gives a ___.

Base; acid.

How does a semiconductor's conduction change when heated?

It conducts more (a metal conducts less).

Connections

Ionisation Energy — the price-tag concept built in §9.
Electronegativity — the mirror "grab" concept, §10.
Periodic Trends — Atomic Radius — the distance idea behind weakening grip, §6.
Acidic and Basic Oxides — chemical payoff of the metal/non-metal split, §12.
Electronic Configuration — how to count valence electrons, §4.
Semiconductors and Doping — the half-free case, §13.
Parent: Metals, non-metals, metalloids — properties

Foundations — Metals, non-metals, metalloids — properties