Atomic Structure
An atom has 15 protons and 16 neutrons. What is its mass number?
31
What is the electron configuration of fluorine (9 electrons)?
2,7
Identify the reaction type:
HCl + NaOH → NaCl + H₂O
Neutralisation
What is always produced in a neutralisation reaction?
Salt and water
Balance this equation:
H₂ + Cl₂ → HCl
H₂ + Cl₂ → 2HCl
Two atoms both have 8 protons, but one has 8 neutrons and the other has 10. What are they called?
Isotopes
An atom has the configuration 2,8,6. Will it gain or lose electrons, and how many?
Gain 2 electrons
Identify the reaction type:
CaCO₃ + HCl → CaCl₂ + H₂O + CO₂
Acid-carbonate reaction
Name the salt formed when hydrochloric acid reacts with sodium hydroxide.
Sodium chloride
Balance this equation:
N₂ + H₂ → NH₃
N₂ + 3H₂ → 2NH₃
An atom has a mass number of 27 and 13 protons. How many neutrons does it have?
14
What ion will be formed by an atom with configuration 2,8,6?
2- (anion)
Identify the reaction type:
Zn + H₂SO₄ → ZnSO₄ + H₂
Acid-metal reaction
Name the salt formed when sulfuric acid reacts with potassium hydroxide.
Potassium sulfate
Balance this equation:
CH₄ + O₂ → CO₂ + H₂O
CH₄ + 2O₂ → CO₂ + 2H₂O
Explain why isotopes of the same element have the same chemical properties.
Because they have the same number of electrons (same electron configuration)
Explain why sodium forms a +1 ion instead of a −7 ion.t is easier to lose 1 electron than gain 7 to achieve a full outer shell
It is easier to lose 1 electron than gain 7 to achieve a full outer shell
Explain how you can recognise an acid-carbonate reaction from its products.
It produces carbon dioxide gas, water, and a salt
Explain how the name of a salt is determined in a neutralisation reaction.
First part comes from the base (metal)
Second part comes from the acid (non-metal)
Balance this equation:
Mg + HCl → MgCl₂ + H₂
Mg + 2HCl → MgCl₂ + H₂
An atom has 17 protons, 18 neutrons, and 17 electrons.
a) What is its mass number?
b) Is this atom neutral or charged? Explain.
a) 35
b) Neutral, because the number of protons equals the number of electrons
Compare how magnesium and fluorine form ions.
Magnesium loses 2 electrons → Mg²⁺
Fluorine gains 1 electron → F⁻
A reaction produces carbon monoxide instead of carbon dioxide. What type of combustion is this and why?
Incomplete combustion, because there is not enough oxygen
Nitric acid reacts with calcium hydroxide. Name the salt formed and explain your reasoning.
Calcium nitrate
Balance this equation:
P₄ + O₂ → P₂O₃
P₄ + 3O₂ → 2P₂O₃