Equations, Group Trends in Periodic Table

Note by ShreyaDas, updated more than 1 year ago
Created by ShreyaDas about 7 years ago


IGCSE Chemistry (C3 The Periodic Table and Equations) Note on Equations, Group Trends in Periodic Table, created by ShreyaDas on 03/31/2014.

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Reactant + Reactant --> ProductWord equation doesn't tell you anything about the proportions in which they react


State symbolssolid (s)liquid (l)gas (g)Substance is dissolved in water - aqueous (aq)

Symbol equation tells us:- which substances are the reactants- which substances are the products- the formula of all the substances involved in the reaction- numbers of moles of all the substances involved - states of all the substances

Rules:1. Write the word equation2. Convert the words into the correct chemical formulae (gaseous elements except for noble gases are diatomic)3. Fill in the state symbols4. Balance the equation- same number of atoms before and after reaction- do not change chemical formulae to balance the equation- only placing whole numbers in front of the formulae can change the proportions of the reactants and products


- When an ionic compound OR strong acid dissolves in water it DISSOCIATES into IONS and becomes a conductor of electricity- When these solutions react, the molecular equation can be simplified by writing an ionic equation

HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)atoms/molecules that didn't change state didn't react = spectator ionsSpectator Ions:  Cl + NaNet Ionic Equation doesn't include spectator ions= H (aq) + OH (aq) --> H2O (l)

Elements are ordered by atomic number (represents the number of protons)Groups: vertical columns where elements have the same number of valence electrons- have similar chemical and physical propertiesPeriods: horizontal rows where electrons are filling the same energy level/shell

Metals on the left = metalsmetals on the right = non-metalsMetalloid = chemical elements that aren't classified

pH of period 3 oxides- going across the groups the pH decreases- metals are basic- non-metals are acidic or neutral- acidic = sulphur dioxide (dissolves in water to form acid rain)- neutral = hydrogen oxide (water) and carbon monoxide 

All oxides of metals can act as bases, but some can act as acidic oxides as well = amphoteric oxides

4 types of oxides:- basic:-- lithium oxide-- sodium oxide- acidic-- sulphur oxide-- chlorine oxide- neutral-- carbon monoxide-- hydrogen oxide (water)- amphoteric-- aluminum oxide-- zinc oxide

Noble Gases- unreactive gases (full electron shell)- 1% of the earth's atmosphere- non-metals- colorless gases

Oxides are used to determine whether an element is a metal or a non-metal.Most non-metals are classed as acidic oxides. While most metals are classed as basicoxides.Acidic Oxides Reacts with water to form acids Neutralises alkaline solution to form salt + water Basic OxidesNeutralises acidic solutions to form salt + waterAmphoeteric OxidesThese are non-metals which display both acidic and basic propertiesAlkaline OxidesReacts with water to form alkaline solutionsNeutral OxidesDo not display either of the acidic or the basic oxides’ properties.

Lithium:  Bubbles seen H2 released Disappears Sodium: Melts and forms a ball as the reaction is exothermic. The heat causes the sodium to melt. Same as Lithium Potassium: Lilac flame seen as the hydrogen burns. Same as sodium

Reacting with water (Mr Rowcliffe ran)



- stored in oil so that they don't react with oxygen- rusted quickly once exposed to air- hydrogen is produced when they react with water- hydroxides are formed (OH)Potassium > Sodium > LithiumReactivity of group 1 metals increase going down the groupall metals rect with water to form strong alkaline solutionsmelting point and hardness decreases as you go down the group


Net Ionic Equations

Periodic Table

More on Oxides

Group 1

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