Atomic Structure
Recall the location and charges of each of the subatomic particles
Proton - Nucleus, Positive Charge
Neutron - Nucleus, Neutral Charge
Electron - Orbits, Negative Charge
Recall the definition of an Ion.
An ion is an atom or group of atoms that has lost or gained electrons and therefore has an electrical charge.
Draw a Bohr (electron shell configuration) diagram for Beryllium
4 electrons
2 in inner shell, 2 in outer shell
What is the pH range for Acids?
1 - 6
Recall the law of conservation of mass:
For any chemical reaction, mass cannot be created or destroyed, only rearranged.
Recall what causes radiation and the three types.
Radiation is caused by an isotope holding too many or too few neutrons, causing the atom to become unstable and decay, producing radiation.
Can release alpha, beta or gamma rays.
Recall the charges of a cation and anion respectively and whether they have gained or lost electrons.
Cation - Positive charge, lost electrons.
Anion - negative charge, gained electrons.
What is the electron configuration of Fluorine?
Atomic number 9
Electron configuration: 2, 7
What is the pH of water?
7
Identify the products and reactions in this chemical reaction:
Silver + sulfur → Silver sulfide
Reactants: Silver and Sulphur
Products: Silver sulfide
Define the term 'Valence Electron'
An electron in the outermost electron shell of an atom that can participate in forming chemical bonds, determining an element's reactivity.
Explain how Lithium becomes an ion (Li+)
Lithium is in group 1, therefore has one valance electron. Lithium loses this one valance electron to form a full outer shell, causing it to become a positively charged cation.
What element has three electron shells and 6 valence electrons?
Sulphur
2, 8, 6 = 16 electrons = atomic number 16
I have a soil that is too acidic for the peas I am growing. What could I add to make the soil less acidic:
- crushed limestone which has a pH of 8
- lemon which has a pH of 2
- water which has a pH of 6.5
Add a substance that is basic to neutralise the soil, so add crushed limestone as it has a pH of 8.
Write the following as a worded chemical reaction:
When sulfuric acid reacts with black powdered copper oxide, a solution of copper sulfate and water are made.
Sulfuric acid + copper oxide → copper sulfate + water
If an element has an atomic number of 6 and an atomic mass of 12 - determine the number of protons, electrons and neutrons that this element has.
6 Electrons
12 - 6 = 6 Neutrons
Determine what ions these elements form:
Calcium and Gallium.
Calcium = group 2 = Ca2+
Gallium = group 3 (13) = Ga3+
What ion do metals usually form?
What ion do non-metals usually form?
Metals = cations
Non-metals = anions
Recall three properties of acids
Corrosive, release H+ ions in the presence of water sour taste, neutralised by bases, turn litmus paper red
Recall the difference between endothermic and exothermic reactions:
Endothermic reactions absorb heat energy from their surroundings, causing the surroundings to cool down. In contrast, exothermic reactions release heat energy into the surroundings, making the surroundings heat up.
Recall the definition of an isotope.
Which of the following are isotopes:
1. Mass number 16, atomic number 8
2. Mass number 17, atomic number 8
3. Mass number 16, atomic number 7
4. Mass number 17, atomic number 9
Isotopes are atoms that have the same number of protons but a different number of neutrons.
1 and 2 are isotopes of oxygen - both have an atomic number of 8, therefore are the same element.
Determine the ionic compound formed by Aluminum and Chlorine (Aluminium chloride)
Al = Al3+
Cl = Cl-
Ionic Comound: AlCl3
Balance the following chemical equation:
S8 + O2 → SO2
S8 + 8 O2 → 8 SO2
What are the products when an acid and a base react?
A student mixes 10.0 g of calcium carbonate (CaCO₃) with hydrochloric acid (HCl). A chemical reaction occurs, producing calcium chloride (CaCl₂), water (H₂O), and carbon dioxide (CO₂). After the reaction is complete, the total mass of the flask and its contents is measured and found to be less than before.
a) Write a balanced chemical equation for the reaction.
b) Identify the type of chemical reaction and justify your choice.
c) Explain why the mass appears to decrease, even though no material was removed from the flask.
CaCO₃ + 2HCl --> CaCl₂ + H₂O+ CO₂
This is an acid + carbonate reaction
The mass would appear to decrease because the product CO2 is a gas and so would have escaped. If the flask was sealed completely, the mass would remain the same.