116 terms

iGCSE Chemistry: Simple molecules & covalent bonding - test myself

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What is meant by the term atom?
An atom is the smallest part of an element
What is meant by the term molecule?
A molecule is made of a fixed number of two or more atoms covalently bonded together
What is the total number of atoms in the formula Be(OH)₂ ?
5
Explain why atoms are neutral
The numbers of electrons and protons are equal
State the mass and charge of a neutron
Neutron: mass=1, charge =0
State the mass and charge of a proton
Proton: mass=1, charge=+1
State the mass and charge of an electron
Electron: mass=almost zero, charge=-1
State the particle that is found in the shells orbiting the nucleus
Electrons
State the particles that are found within the nucleus of an atom
Protons and neutrons
What are the three subatomic particles?
protons, neutrons and electrons
What are the two parts of an atom?
The nucleus and the electron shells
Which particle in an atom has a negative charge?
Electron
Which particle in an atom has a posiive charge?
proton
Which particle in an atom has the smallest mass?
Electron
How many neutrons in a typical atom of carbon?
6
How many neutrons in a typical atom of fluorine?
10
How many neutrons in a typical atom of hydrogen?
0
How many neutrons in a typical atom of magnesium?
12
How many neutrons in a typical atom of sulfur?
14
How many protons in a fluorine atom?
9
How many protons in a helium atom?
2
How many protons in a hydrogen atom?
1
How many protons in a phosphorus atom?
15
How many protons in a potassium atom?
19
How many protons in a silicon atom?
14
How many protons in a sodium atom?
11
In terms of mass and atomic number, what are isotopes?
Isotopes are atoms with the same atomic number but a different mass
In terms of subatomic particles, what are isotopes?
Isotopes are atoms with the same number of protons but with a different number of neutrons
Tritium, an isotope of hydrogen, has a mass number of 3. How many neutrons does an atom of tritium contain?
2
What are isotopes?
Isotopes are atoms of the same element (same number of protons) but with a different number of neutrons (different mass)
What is a mass number?
Mass number is the number of protons plus the number of neutrons in an atom
What is an atomic number?
The atomic number is the number of protons in an atom
What is meant by the term relative atomic mass, Aᵣ?
The average mass of an atom of an element, relative to 1/12th of the mass of an atom of carbon-12
What is the atomic number of a beryllium atom?
4
What is the atomic number of a boron atom?
5
What is the atomic number of a calcium atom?
20
What is the atomic number of a carbon atom?
6
What is the atomic number of a chlorine atom?
17
What is the atomic number of an argon atom?
18
What is the atomic number of an oxygen atom?
8
What is the relative atomic mass (Aᵣ) of a helium atom?
4
What is the relative atomic mass (Aᵣ) of a hydrogen atom?
1
What is the relative atomic mass (Aᵣ) of a potassium atom?
39
What is the relative atomic mass (Aᵣ) of a silicon atom?
28
What is the relative atomic mass (Aᵣ) of a sodium atom?
23
How are elements arranged in the periodic table?
in order by atomic number
On the Periodic table what is the meaning of the word Group?
A Group is a vertical column of similar elements
On the Periodic Table what is the meaning of the word Period?
A Period is a horizontal row of elements
How many electron shells do the elements in the second period have?
2
How many electron shells do the elements in the third period have?
3
How many electrons can the first shell hold?
2
How many electrons can the first, second and third shells hold?
First 2, second 8, third 8
How many electrons can the second shell hold?
8
How many electrons can the third shell hold?
8
How many electrons in a calcium atom?
20
How many electrons in a chlorine atom?
17
How many electrons in a helium atom?
2
How many electrons in a magnesium atom?
12
How many electrons in a nitrogen atom?
7
How many electrons in a sodium atom?
11
How many electrons in an argon atom?
18
How many electrons in the outer shell of group 1 elements?
1
How many electrons in the outer shell of group 2 elements?
2
How many electrons in the outer shell of group 3 elements?
3
How many electrons in the outer shell of group 4 elements?
4
How many electrons in the outer shell of group 5 elements?
5
How many electrons in the outer shell of group 6 elements?
6
How many electrons in the outer shell of group 7 elements?
7
Write the electronic configuration of argon
2,8,8
Write the electronic configuration of potassium
2,8,8,1
Where are metals found on the periodic table?
On the left, reaching across the middle
Where are non-metals found on the periodic table?
At the top right, plus hydrogen
Where are the transition metals on the Periodic Table?
In the middle
On the Periodic table what is the meaning of the word Group? What does that tell us about the electron configuration of the atom?
same number of electrons in the outer shell
On the Periodic Table what is the meaning of the word Period? What does that tell us about the electron configuration of the atom?
same number of electron shells
Explain, in terms of electrons, why isotopes have the same chemical properties
Isotopes have the same number of electrons
Why do elements in the same group of the periodic table have similar chemical properties?
Elements in the same group of the periodic table have the same number of electrons in their outer shell
Explain, in terms of the arrangement of electrons in its atoms, why neon is very unreactive
Neon has 8 electrons in the outer shell, so it is full. Therefore it does not easily gain or lose electrons
What are the elements in group 0 called?
Noble gases
What is special about the elements in group 0?
They are very unreactive (because they have full outer electron shells)
Which group of atoms has a full outer shell?
Group 0, the noble gases
Describe the formation of a covalent bond
The sharing of a pair of electrons between two nuclei
How can atoms get a full outer shell?
Either the transfer (ionic) or sharing (covalent) of electrons
Explain how the atoms are held together in a hydrogen bromide molecule
A shared pair of electrons is attracted to BOTH nuclei
Give the definition of a covalent bond
Strong electrostatic attraction between a shared pair of electrons and two nuclei
Draw a dot and cross diagram to show the covalent bonding in a molecule of ammonia, NH₃
Draw a dot and cross diagram to show the covalent bonding in a molecule of carbon dioxide, CO₂
Draw a dot and cross diagram to show the covalent bonding in a molecule of chlorine, Cl₂
Draw a dot and cross diagram to show the covalent bonding in a molecule of ethane, C₂H₆
Draw a dot and cross diagram to show the covalent bonding in a molecule of ethene, C₂H4
Draw a dot and cross diagram to show the covalent bonding in a molecule of hydrogen chloride, HCl
Draw a dot and cross diagram to show the covalent bonding in a molecule of hydrogen, H₂
Draw a dot and cross diagram to show the covalent bonding in a molecule of methane, CH₄
Draw a dot and cross diagram to show the covalent bonding in a molecule of nitrogen, N₂
Draw a dot and cross diagram to show the covalent bonding in a molecule of oxygen, O₂
Draw a dot and cross diagram to show the covalent bonding in a molecule of water, H₂O
Explain why carbon dioxide gas, CO₂, is a gas at room temperature
Carbon dioxide has a simple molecular structure with weak intermolecular forces that require little energy to overcome
Explain why methane gas, CH₄, is a gas at room temperature
Methane has a simple molecular structure with weak intermolecular forces that require little energy to overcome
Explain why nitrogen gas, N₂, is a gas at room temperature
Nitrogen has a simple molecular structure with weak intermolecular forces that require little energy to overcome
If a substance has a simple molecular structure, what physical state might it be at room temperature?
Gas or liquid (low melting point)
Do larger molecules have higher or lower boiling points than smaller molecules?
Higher
Why is the boiling point of a larger molecule higher than that of a smaller molecule?
Larger molecules have more attractions between them which must be overcome when a substance boils
Why is the melting point of a smaller molecule lower than that of a larger molecule?
Larger molecules have more attractions between them which must be overcome when a substance melts
A gas is bubbled through limewater and the limewater goes cloudy. Identify the gas.
Carbon dioxide
Describe the test for ammonia gas
Turns damp red litmus paper blue
Describe the test for carbon dioxide gas
Bubble the gas through limewater and see if it goes cloudy
Describe the test for chlorine gas
Turns moist litmus paper white (bleaches)
Describe the test for hydrogen gas
Use a lit splint to see if the gas pops
Describe the test for oxygen gas
Use a glowing splint and see if it relights
In the test of a gas, a glowing splint relights. What is the gas?
Oxygen
In the test of a gas, a lit splint gives a squeaky pop. What is the gas?
Hydrogen
Which gas will bleach moist litmum paper?
Chlorine
Which gas will turn damp red litmus paper blue?
Ammonia
Describe the chemical test for water
Add water to anhydrous copper(II) sulfate which will change from white to blue if water is present
What colour is anhydrous copper (II) sulfate?
White
What colour is hydrated copper (II) sulfate?
Blue