Chemistry Paper 1 Flashcards
What are all substances made up of?
Atoms.
Define atom.
The smallest part of an element that can exist.
What is the chemical symbol for sodium?
Na
What is the chemical symbol for chlorine?
Cl
What is the chemical symbol for hydrogen?
H
What is the chemical symbol for iron?
Fe
Roughly how many different elements are there?
100
In which table can we find the elements?
The periodic table.
What type of reactions form compounds from elements?
Chemical reactions.
Define compound.
A substance made from two or more different elements that have been chemically joined together.
We can write reactions as word equations and___________ equations.
Symbol.
Write the chemical formula for a hydroxide ion.
OH-
Write the chemical formula for a nitrate ion
NO3-
Write the chemical formula for a carbonate ion
CO32-
Write the chemical formula for a sulphate ion
SO42-
Define element
A substance made of only one type of atom
Define mixture.
A substance made up of two or more elements or compounds not chemically joined together.
When a mixture is formed, do the chemical properties of the substances used to make the mixture change?
No.
What type of processes separate the components of a mixture?
Physical processes.
State the five main separating techniques.
1) Filtration
2) Crystallisation
3) Simple distillation
4) Fractional distillation
5) Evaporation
What does filtration involve?
It involves separating an insoluble solid from a liquid.
During evaporation, what is evaporated, the solvent or the solute?
The solvent.
When salty water is heated and the liquid evaporated, what is left behind?
Crystals of salt.
Three liquids with very different boiling points are present in a mixture. Which separation technique would you use to separate them?
Simple distillation.
When would fractional distillation be used instead of simple distillation?
When the liquids making up a mixture have similar boiling points.
What did John Dalton describe atoms as?
Round spheres that could not be divided.
Describe J J Thomson’s plum pudding model of the atom.
The atom is a ball of positive charge with negative electrons embedded in it.
What was the name of the experiments carried out by Rutherford and Marsden?
Alpha particle scattering experiments
What did Rutherford and Marsden fire alpha particles at?
A thin sheet of gold foil.
What did Rutherford and Marsden observe from their experiments that surprised them?
Most alpha particles went straight through the foil. But a few were scattered in different directions. Some even deflected backwards
What did Rutherford and Marsden conclude about the structure of the atom from their experiments?
That the mass of an atom was concentrated at the centre (nucleus), and that the nucleus was positively charged. Most of the atom is empty space.
Who adapted the nuclear model by suggesting that electrons orbit the nucleus at specific distances?
Niels Bohr.
The experimental work of James Chadwick provided the evidence for which subatomic particle?
The neutron.
What is the relative charge of a proton?
+1
What is the relative charge of an electron?
-1
What is the relative charge of a neutron?
0
Why do atoms have no overall charge?
1) Protons are +1 and electrons have -1
2) Atoms have the same number of protons and electrons so the charges cancel out
Do atoms of different elements have the same or different number of protons?
Different
Do atoms of the same elements have the same or different number of protons?
Same
What does the atomic number of an element tell us?
The number of protons in an atom of that element.
How many protons does Mg have?
12
Have many protons does Cl have?
17
Roughly what is the radius of an atom?
1 x 10-10 m
Roughly what is the radius of the nucleus of an atom?
1 x 10-14 m
Almost all of the mass of an atom is situated where?
The nucleus.
What is the relative mass of an electron?
Very small.
What is the relative mass of a neutron?
1
What is the relative mass of a proton?
1
What does the mass number of atom tell us?
The total number of protons and neutrons in the atom.
Atoms of the same element can have different number of neutrons. What are they called?
Isotopes.
How many neutrons are there in an atom on Na?
12
How many protons are there in an atom of Na?
11
How many electrons are there in an atom of Na?
11
How many neutrons are there in an atom on F?
10
How many protons are there in an atom of F?
9
How many electrons are there in an atom of F?
9
Cu - 63 has an abundance of 69.2% and Cu-65 has an abundance of 30.8%. Calculate the relative atomic mass of copper to 1 decimal place.
63.6
Cl-35 has an abundance of 75% and Cl-37 has an abundance of 25%. Calculate the relative atomic mass of copper to 1 decimal place.
35.5
What is the maximum number of electrons that can go in the first electron shell?
2
What is the maximum number of electrons that can go in the second electron shell?
8
What is the maximum number of electrons that can go in the third electron shell?
8
Write the electronic structure for sodium.
2, 8, 1
Write the electronic structure for nitrogen.
2, 5
Write the electronic structure for silicon.
2, 8, 6
Write the electronic structure for neon.
2, 8
The elements in the periodic table are arranged in order of…
Atomic number
Elements in the same group have….
Similar properties
What are the vertical columns called?
Groups
What are the horizontal rows called?
Periods
Elements in the same group have a different number of electrons in their outer shell. True or False?
False.
Elements with the same number of outer electrons have similar chemical properties. True or False?
True.
Would you expect magnesium and nitrogen to have similar properties, why?
No, they are in different groups and have a different number of outer shell electrons.
Would you expect fluorine and chlorine to have similar properties, why?
Yes, because they are in the same group and have the same number of outer shell electrons.
Before the discovery of electrons, neutrons protons, scientists tried to classify elements by arranging them in order of what?
Their atomic weight.
State one problems of the early periodic tables.
Some elements were placed in inappropriate groups.
Which scientist overcame some of the problems of the early periodic tables?
Mendeleev.
State two changes Mendeleev made to overcome some of the problems of the early periodic tables.
1) He left gaps for elements that he thought had not been discovered
2) In some places he also changed the order based on atomic weights (swap places)
State two discoveries that supported Mendeleev’s changes to the early periodic tables.
1) Elements with properties predicted by Mendeleev were discovered and filled the gaps.
2) The discovery of isotopes made it possible to explain why the order based on atomic weights was not always correct.
What name is given to elements that react to form positive ions?
Metals
What name is given to elements that do not form positive ions?
Non-metals
Are the majority of elements metal or non-metals?
Metals
Where are metals found on the periodic table?
To the left and towards the bottom of the periodic table
Where are non-metals found on the periodic table?
Towards the right and top of the periodic table
State three physical properties of metals
1) Strong/hard
2) Malleable
3) Good electrical and thermal conductors
5) Shiny
4) High melting and boiling points
State two physical properties of non-metals
1) Tend to be dull looking
2) normally brittle
3) Don’t generally conduct electricity
What name is given to elements in group 0?
The noble gases
The elements in group 0 are inert, what does this mean?
They are unreactive.
Why are the elements in group 0 inert?
They have a stable arrangement of electrons.
How many outer shell electrons do most of the elements in group 0, what is the exception?
8, the exception is helium, it has 2.
How does the boiling point change as you go down group 0?
It increases.
Why does the boiling point change as you go down group 0?
Increase in the number of electrons so greater intermolecular forces
What are the elements in group 1 known as?
The alkali metals
Why do group 1 metals have similar properties?
The all have one electron in their outer shell
How are alkali metals different to other metals?
They are soft and have a low density
How does the reactivity change as you go down group 1?
The reactivity increases
How does the boiling melting point change as you go down group 1?
It decreases
Name the products when sodium reacts with water.
sodium hydroxide and hydrogen
Write the chemical formula of the products formed when potassium reacts with water.
KOH and H2
Write a word equation for the reaction between lithium and oxygen.
lithium + oxygen -> lithium oxide
Explain why potassium is more reactive than lithium (3 marks)
More shells/electrons, less shielding (or weaker attraction from nucleus), easier to lose electrons
What are the elements in group 7 known as?
The halogens
Why do elements in group 7 have similar reactions?
They all have 7 electrons in their outer shell.
Are group 7 elements metals or non-metals?
Non-metals
The halogens consist of molecules made up of pairs of atoms. True or False?
True.
What state is fluorine at room temperature?
Gas
What state is chlorine at room temperature?
Gas
What state is bromine at room temperature?
liquid
What state is iodine at room temperature?
solid
What is a displacement reaction?
A reaction in which a more reactive element takes the place of a less reactive element in a compound
Explain why the following reaction does not proceed: KBr + I₂
Iodine is less reactive than bromine so cannot displace it
Balance the equation and explain why it is a displacement reaction: KBr + Cl₂ → KCl + Br₂
2KBr + Cl₂ → 2KCl + Br₂ , chlorine has displaced bromine as it is more reactive
Explain why fluorine is more reactive than chlorine
Fewer shells/electrons, less shielding (or stronger attraction from nucleus), easier to gain electrons
How do the boiling and melting point change as you go down group 7?
The boiling and melting point increase
How does reactivity change as you go down group 7?
The reactivity decreases
State the three types of chemical bonds.
Ionic, covalent and metallic.
Fill in the blank. For _______ bonding the particles are oppositely charged ions.
Ionic
Fill in the blank. For ________ bonding the particles are atoms which share pairs of electrons.
Covalent
Fill in the blank. For _________ bonding the particles are atoms which share delocalised electrons.
Metallic
What type of elements does ionic bonding occur between?
Metals and non-metals
What type of elements does covalent bonding occur between?
Non-metals
Define ionic bonding.
The electrostatic force of attraction between positive metal ions and negative non-metal ions.
Do metal atoms for positive or negative ions?
positive
Do non-metal atoms form positive or negative ions?
negative
Na has an electronic structure of 2, 8, 1. State the electronic structure of a sodium ion
2, 8
State the charge for the ions of group 1
+1
State the charge for the ions of group 2
+2
State the charge for the ions of group 7
-1
State the charge for the ions of group 7
-2
What type of bonding would occur between group 1 and group 7 ions?
Ionic bonding
State the charge of the ions present in MgCl2
Mg2+ and Cl-
Cl has an electronic structure of 2, 8, 7. State the electronic structure of a sodium ion
2, 8
What type of forces hold ions in an ionic compounds together?
Electrostatic forces of attraction
An ionic compound is a giant structure of ions? True or false?
True.
What name is given to structures formed by ionic bonding?
Giant ionic lattice
Describe the direction of the forces in an ionic structure.
In all directions
How many shared pair of electrons are there in one covalent bond?
1
How many electrons are there in one covalent bond?
2
How many electrons are there in 2 covalent bonds?
4
When atoms share electrons what type of bonds do they form?
Covalent bonds
What type of bonding is present in a molecule of NH3
Covalent
How many covalent bonds can carbon form?
4
How many covalent bonds are there in CH4?
4
Covalently bonded substances never consist of small molecules. True or False?
False.
Polymers are examples of very large molecules that have covalent bonds. True or False?
True.
Describe the structure of metals.
Consist of metal ions arranged in a regular pattern in a sea of delocalised electrons.
What does delocalised mean?
Free to move.
Which electrons of a metal are delocalised? (hint - shells)
The electrons in the outer shell
What are the three states of matter?
Solid, liquid and gas
What two physical processes take place at the melting point?
Melting and freezing
What two physical processes take place at the boiling point?
Condensation and boiling
Describe the layout of particles in a solid.
They are tightly packed in neat rows.
What happens to the particles of a solid as it is heated?
The particles gain energy and start to vibrate more.
The amount of energy needed to change state depends on the strength of what?
Forces between particles
The stronger the forces between particles the _________ the melting and boiling point of a substance.
Higher
State a limitation of using spheres to represent particles in the particle model.
1) Particles aren’t solid spheres
2) Particles aren’t inelastic
Oxygen has a melting point of -219oC and a boiling point of -183oC. What state is oxygen at -200oC?
Liquid
Why is energy required for a liquid to boil into a gas?
To overcome the forces of attraction holding the particles in a liquid together.
Which state of matter does not have a fixed volume and shape?
Gas
Which state of matter has a fixed volume, but does not have a fixed shape?
Liquid
What state symbol is used for solids?
(s)
