1.1) Atomic Structure and the Periodic table Flashcards
Which of the following make up the nucleus of an atom?
Proton, Neutron
What is the charge on a proton?
Positive
Which particle determines what element an atom is?
Proton
Which particles within an atom have a relative mass of 1?
Proton, neutron
Which sub-atomic particle does NOT have a charge?
Neutron
What do we call an atom that has a positive or negative charge?
Ions
What is an isotope?
Isotopes are atoms with the same number of protons, but different numbers of neutrons.
An atom has 13 protons and 14 neutrons. What is its mass number?
27
True or false? Something counts as a ‘molecule’ when it’s made from 2 or more atoms, and those atoms are held together by chemical bonds.
True
O2 consists of 2 oxygen atoms, covalently bonded together. Does oxygen count as a molecule?
YES
What are molecules?
A molecule consists of 2 or more atoms
What is a compound?
A compound is a substance made from two or more different elements that are chemically bonded together.
Is carbon dioxide (CO2) a molecule, a compound, or both?
Both (CO2 is a molecule because it contains 3 atoms chemically bonded together. It is also a compound as it contains atoms of 2 elements (carbon and oxygen))
What is a mixture?
A mixture consists of 2 or more substances that are not chemically bonded.
Is the air all around us a compound or a mixture?
Mixture - Air contains many different substances, such as N2, O2, and CO2. Importantly, these substances are not chemically bonded to each other, so air is a mixture.
Is seawater a compound or a mixture?
Mixture - Seawater contains many different substances, mainly H2O and salts like NaCl, but also lots of other substances. Importantly though, these substances are not chemically bonded to each other, so seawater is a mixture.
Balance the following chemical equation:
Mg + O2 ➔ 2MgO
2Mg + O2 ➔ 2MgO
Balance the following chemical equation:
N2 + H2 ➔ NH3
N2 + 3H2 ➔ 2NH3
When representing oxygen in a symbol equation, should you write ‘O’ or ‘O2’?
O2 - Oxygen exists as a diatomic molecule, which means that each molecule contains 2 atoms, hence O2.
Balance the following chemical equation:
CH4 + O2 ➔ CO2 + H2O
CH4 + 2O2 ➔ CO2 + 2H2O
Choose the correct balanced equation for the reaction of iron and chlorine:
?Fe + ?Cl2 ➔ ?FeCl3
2Fe + 3Cl2 ➔ 2FeCl3
Choose the correct balanced equation for the reaction of sodium with water:
2Na + H2O ➔ NaOH + 2H2
Na + H2O ➔ 2NaOH + H2
2Na + 2H2O ➔ 2NaOH + H2
2Na + 2H2O ➔ 2NaOH + H2
What is a solvent?
A solvent is a liquid in which substances can dissolve.
A small amount of sodium chloride is dissolved into a beaker of water. Which of the following is the solvent?
Sodium chloride
Water
Beaker
Water
what is a soluble solid?
Solid substances that can dissolve in liquids are described as soluble.
What are insoluble solids?
Solids that cannot dissolve are described as insoluble.
True or False? Filtration involves using a Bunsen burner flame to evaporate a solvent from a solution.
False - No, that process is called ‘evaporation’ not ‘filtration’.
What is the best method to obtain a sample of salt from a salt solution?
Evaporation
Describe how you would carry out the process of crystallisation.
First, pour the solution into an evaporating dish and heat it using a Bunsen burner. Stop heating it when crystals start to form (‘point of crystallisation’) and allow it to cool down. Then either leave it to allow the rest of the water to evaporate, or filter out the crystals using filter paper and a funnel. Lastly, dry the crystals in a warm oven.
How would you separate pieces of rock from a solution of salt water?
Filtration
The steps of simple distillation:
A solution is heated, usually using a Bunsen burner. The liquid in the mixture evaporates into a gas. The gas is cooled by a water jacket, and condenses into a liquid, which then flows into the beaker.
Which piece of equipment is highlighted in the image above?
Fractionating column
Which piece of equipment is highlighted in the image above?
Boiling flask
Which piece of equipment is highlighted in the image above?
Cooling jacket
Which piece of equipment is highlighted in the image above?
Condenser
Which piece of equipment is highlighted in the image above?
Beaker
Fractional distillation can separate a mixture of several liquids that each have different:
Boiling points
Briefly explain the process of fractional distillation to separate a mixture of the liquids methanol, ethanol and propanol.
Heat is applied and the liquid with the lowest boiling point evaporates and condenses into a beaker.If other liquids evaporate by chance, they condense in the fractionating column back into the flask.The temperature is altered to repeat the process for the second liquid. The three liquids are separated based on differing boiling points with the third remaining in the flask.
How would you isolate pure water from salt water?
Simple distillation
When Democritus first conceived of atomic theory, around 500 BC, how did he describe atoms?
- Small spheres
- Separated from each other by empty space
- The smallest possible unit of matter
In 1897 J. J. Thomson theorised that an atom consisted of a ball of positive charge, with negative electrons mixed throughout it. What do we call this model?
Plum pudding model
How Rutherford developed the nuclear model?
In Rutherford’s experiments, alpha particles were fired at a thin sheet of gold foil.
Most particles passed through, but some were deflected off course. This caused him to hypothesise that there was a dense region of positive charge at the centre of the atom that repelled the alpha particles. As a result he developed the nuclear model of the atom, in which there was a central positive nucleus, surround by negative electrons.
One issue with Rutherford’s nuclear model was that the atom should collapse as the negative electrons would be attracted to the positive nucleus, causing them to rush inwards.
In response to this, in 1913 Bohr suggested that electrons ___________________, which prevents the atom from collapsing.
orbit the nucleus in shells
In the 20th century, Chadwick discovered neutral particles in the atomic nucleus. What are these particles called?
Neutrons
An atom of potassium has 1 electron in its outermost shell.
In a chemical reaction, will potassium gain or lose 1 electron?
Lose - Atoms are unstable when they have an incomplete shell of electrons. This means potassium will ‘want’ to lose one electron, leaving it with three complete shells.
State three general properties of metals:
Sonorous (produce a ringing sound when struck)
Good conductors of heat
Malleable
Properties of Metals :
Metals are very strong, as the ions are held together by metallic bonds.
They also tend to be malleable, which means they can bend without breaking.
Non-metals, in contrast, break easily, and so are said to be brittle.
Many transition metals can be used as catalysts. What is the definition of a catalyst?
A substance that can speed up a chemical reaction without being used up
True or false? Elements within a period show similar chemical properties to each other.
False
Elements within the same group have similar chemical properties.
The atoms of elements in the same group have the same number of:
Electrons in their outer shell
The alkali metals in group 1 of the periodic table all have how many electrons in their outer shell?
1
What is chorines atomic number?
What group is it in?
Chlorine has an atomic number of 17.
It’s in group 7 of the periodic table.
This means it has 7 electrons in its outer shell, and has similar chemical properties to the other elements in the same group
The atoms of elements in the same period have the same number of:
Shells
When metal atoms react, do they lose or gain electron(s) from their outer shell.
lose
This creates a positive charge.
Give two properties of the Group 1 metals:
- soft
- reactive
Trends in the chemical and physical properties of group 1 elements.
more / less / increase / decrease
As you go down group 1, the metals become
reactive.
Their melting and boiling points
.
- As you go down group 1, the metals become MORE reactive.
- Their melting and boiling points DECREASE
Explain why the reactivity of group 1 metals increases as you go down the group.
The atomic radius increases down the group (the atoms get larger).
The force of attraction between the nucleus and outer electron decreases.
The electron is lost more easily (requires less energy to remove) from atoms lower down the group.
Alkali metals react with water. Which two products are formed?
Metal hydroxide
Hydrogen
(Alkali metal + water ➔ metal hydroxide + hydrogen)
The group 1 metals can react with the non-metals in group 7.
When sodium reacts with chlorine it forms an ionic salt called _______________
When solid, the normal color of this salt is ______
- Sodium Chloride.
- White
Some of the compounds formed when alkali metals react with oxygen can be a bit confusing. It’s best to just memorize these ones:
- Lithium reacts with oxygen to form lithium oxide, Li2O.
- Sodium reacts with oxygen to form sodium oxide, Na2O or sodium peroxide, Na2O2.
- Potassium reacts with oxygen to form potassium peroxide, K2O2, or potassium superoxide, KO2.
For questions involving halogen displacement reactions, you will often be asked about the color changes that take place.
The key information to remember is:
- Halide salts (e.g. KCl, KBr, KI) are colorless
- Bromine water is orange
- Chlorine water is colorless
- Iodine water is brown
This means that when you mix chlorine water, bromine water, or iodine water with a halide salt you may get a color change.
Colors and physical states of the halogens at room temperature
solid / gas / liquid / green / yellow / grey
1) Fluorine is a poisonous________ colored gas and is the most reactive halogen
2) Chlorine is a ____colored gas.
3) Bromine is a red-brown volatile ________ which is also poisonous.
4) Iodine is a __________ colored solid with purple vapours.
1) yellow
2) green
3) liquid
4) grey
Which two properties are seen in group 7 elements?
They can form covalent bonds with other non-metals
Their ions usually have a 1- charge
Do the melting and boiling points of the halogens increase or decrease as you go down the group?
Increase
Based on the reactivity of the halogens, which of these displacement reactions is possible?
2HBr + F2 ➔ 2HF + Br2
2HF + Cl2 ➔ 2HCl + F2
2HCl + I2 ➔ 2HI + Cl2
2HBr + F2 ➔ 2HF + Br2
Fluorine is more reactive than bromine and so the fluorine can displace the bromine in HBr.
double / diatomic / covalent / ionic
The halogens exist as _______ molecules, meaning each molecule consists of two atoms.
The two atoms are joined by a ___________bond, which allows each atom to share an electron, giving each atom a full outer shell.
diatomic
covalent
Are noble gases flammable?
no
Why are the noble gases inert?
(‘inert’ means chemically unreactive)
The atoms have a full outer shell of electrons
