Unit 1: Fundamental Particles Flashcards
Define atom
The smallest part of an element that can still be recognised as that element
Define element
A substance made of only one type of atom
Define compound
A substance made of more than one atom chemically bonded together (can be atoms of the same type!)
Define molecule
A substance made of more than one atom chemically bonded together (can be atoms of the same type!)
Define mixture
A substance made of more than one thing not chemically bonded together
State the three subatomic particles
Protons, neutrons, electrons
State the masses of the subatomic particles
Protons: 1, neutrons: 1, electrons: Very Small
State the relative charges of the subatomic particles
Protons: +1, neutrons: 0, electrons: -1
How are the subatomic particles arranged in an atom? (3 marks)
Protons and neutrons in the nucleus, electrons orbiting in shells
What is the plum pudding model of the atom?
A ball of positive charge with negative electrons studded into it
What did the gold foil experiment prove?
That atoms have dense nucleuses with a positive charge
What is the atomic number of an atom?
The number of protons in an atom
What is the mass number of an atom?
The number of protons + the number of neutrons in an atom
How do you calculate the number of neutrons in an atom?
Mass number - atomic number
How are the electrons arranged in atoms?
Orbiting the nucleus in shells
How many electrons can go in the first shell?
2
How many electrons can go in the second and third shells?
8
What are groups in the periodic table?
The columns, numbered 1, 2, 3, 4, 5, 6, 7, 0
What can the group tell you about the electrons in an atom?
How many electrons in the outer shell. E.g. carbon is in group 4 so has 4 electrons in the outer shell
What are periods in the periodic table?
The rows in the periodic table
What can the period tell you about the electrons in an atom?
How many shells an atom has. E.g. carbon is in the second period so has two shells
Why did Mendeleev put some elements in groups?
Because they had similar chemical properties (e.g. they reacted violently with water)
What order did Mendeleev put the elements?
In order of atomic weight
Why did Mendeleev leave gaps in his periodic table?
For elements that had not been discovered yet
What is an ion?
an atom which has lost or gained an electron
In terms of electrons, what do group 1 elements have in common?
1 electron in the outer shell
In terms of electrons, what do group 7 elements have in common?
7 electrons in the outer shell
In terms of electrons, what do group 0 elements have in common?
Full outer shell
Explain why the noble gases are inert
They have full outer shells, so do not need to gain or lose electrons
What happens to the size of the atoms as you go down a group?
They get bigger by one energy shell
What happens to the reactivity of the halogens (group 7 elements) as you go down the group?
They become less reactive
What happens to the reactivity of the alkali metals (group 1 elements) down the group
They become more reactive
Name LiOH
Lithium hydroxide
Name KOH
Potassium hydroxide
Explain why the group 1 elements are called alkali metals
They are metals that form alkalis when they react with water
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 + Iā
Iodine is less reactive than bromine so cannot displace it
Explain why fluorine is more reactive than chlorine
Fewer shells/electrons, less shielding (or stronger attraction from nucleus), easier to gain electrons
Explain why potassium is more reactive than lithium (3 marks)
More shells/electrons, less shielding (or weaker attraction from nucleus), easier to lose electrons
Explain why bromine is less reactive than chlorine (3 marks)
More shells/electrons, more shielding (or weaker attraction from nucleus), harder to gain electrons
Explain why sodium is less reactive than caesium (3 marks)
Fewer shells/electrons, less shielding (or stronger attraction from nucleus), harder to lose electrons
