Yr 10 Atomic Structure

Physical Change

A change where no new substances are formed, typically involving a change of state (e.g., melting ice) or shape, where the chemical composition remains the same.

Chemical Change

A change where a new substance is formed through the breaking and making of chemical bonds, often indicated by color changes, temperature changes, gas production, or mass changes.

Reactants and products

Reactants are the starting chemicals in a reaction, and products are the new substances formed by the reaction.

Element arrangement in periodic table

They are arranged in order of increasing atomic number, with rows called periods and columns called groups.

Metals and non-metals in periodic table

Metals are located on the left side, and non-metals are located on the right side.

Number of valence electrons

Its group number (e.g., Group 1 has 1 valence electron, Group 2 has 2, Group 13 has 3, up to Group 18 which has 8).

Period Number

The total number of electron shells that the element's atoms possess (e.g., Period 2 elements have 2 electron shells).

Groups

They have the same number of valence electrons and share similar chemical properties and reactions.

Hydrogen, Helium, Lithium, Beryllium

H, He, Li, Be

Boron, Carbon, Nitrogen, Oxygen

B, C, N, O

Fluorine, Neon, Sodium, Magnesium

F, Ne, Na, Mg

Aluminium, Silicon, Phosphorus, Sulfur

Al, Si, P, S

Chlorine, Argon, Potassium, Calcium

Cl, Ar, K, Ca

Silver, Gold, Barium, Bromine

Ag, Au, Ba, Br

Copper, Iron, Lead, Zinc

Cu, Fe, Pb, Zn

Protons and electrons

The number of protons is equal to the atomic number, and the number of electrons equals the number of protons.

Neutrons

Subtract the atomic number from the mass number (Neutrons = Mass Number - Atomic Number).

Why are atoms overall neutral?

Because they contain equal numbers of positive protons and negative electrons, meaning the charges cancel each other out.

Ions

A charged particle formed when an atom gains or loses electrons in order to achieve a full valence shell and become stable.

How atoms form ions

They lose their valence electrons to form positive ions (cations) with a full outer shell.

Non-metal ions

They gain valence electrons to form negative ions (anions) with a full outer shell.

Ionic Bonding

The electrostatic attraction between oppositely charged ions (a metal cation and a non-metal anion) formed via the transfer of electrons.

Metallic Bonding

The electrostatic attraction between positively charged metal cations arranged in a lattice and a moving "sea" of delocalized valence electrons.

Covalent Bonding

The bonding that occurs between non-metal atoms when they share pairs of electrons to achieve full valence shells.

5 diatomic elements

Oxygen (O2), Hydrogen (H2), Fluorine (F2), Chlorine (Cl2), and Nitrogen (N2).

Water and Carbon Dioxide Chemical Formula

Water is H2O and Carbon dioxide is CO2.

Brackets in ionic formula

When there is more than one of a polyatomic ion present in the compound (e.g., Ca(NO3)2).

Hydroxide

OH