Atomic Theory
The smallest unit of an element
Atom
How is the periodic table organised?
It is organised by increasing atomic number.
What is the chemical symbol for water?
H20
Why is it important to balance chemical equations?
Balancing equations ensures that the law of conservation of mass is obeyed.
What is the basis of a chemical reaction?
It is when atoms/elements are rearranged to create a new substance
The three subatomic particles found in an atom
Proton Neutron Electron
The symbol for gold on the periodic table
Au
In a chemical equation, what do the coefficients represent?
The coefficients represent the relative ratios of reactants and products in the reaction.
Balance the chemical equation: Fe + O2 → Fe2O3
4Fe + 3O2 → 2Fe2O3
Name four types of chemical reactions.
The four main types of chemical reactions are composition, decomposition, displacement, and precipitation, combustion, corrosion, endo/exo thermic
The number of electrons in a neutral atom
Equal to the number of protons / atomic number
The group of elements on the periodic table known as the "noble gases"
Group 18
Balance the chemical equation: CH4 + O2 → CO2 + H2O
CH4 + 2O2 → CO2 + 2H2O
What are coefficients in a chemical equation used for?
Coefficients are used to adjust the number of atoms or molecules to balance the equation.
What occurs in a precipitate reaction?
When 2 aqueous solutions are mixed the dissolved ions can bond creating a new ionic compound, one of which will be a solid or insoluble.
The atomic number of an element
The atomic number represents the number of protons in an element.
What trend does atomic radius follow across a period on the periodic table?
Atomic radius decreases across a period from left to right
What is the law of conservation of mass in chemical equations?
It states that the total mass of reactants must equal the total mass of products in a chemical reaction.
In a balanced chemical equation, what should the sum of the coefficients be for reactants and products?
The sum of the coefficients for reactants and products should be equal.
When a solution of barium hydroxide reacts with ammonium hydroxide, the temperature of the products becomes low enough to freeze water.
What type of reaction is this? Is energy transferring to or from the reactants?
This is an endothermic reaction as the heat is taken from the environment causing the reaction to feel cold. The energy is absorbed by the reactants for the reaction to take place.
The subatomic particle that determines the element
The protons, elements can have different amount of electrons and neutrons
What accounts for the reactivity in the elements?
How easy it is for electrons to be lost or gained
Define a chemical reaction.
A chemical reaction is a process in which substances (reactants) transform into new substances (products) with different chemical properties.
How is a worded equation different to a chemical equation?
Word equations don’t include the formulae of the chemicals. Chemical equations include the state and also the amount of atoms involved.
What are the products of the reaction between silver nitrate and sodium chloride?
Silver chloride and sodium nitrate