C1 Atomic Structure and Periodic Table 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 two or more different atoms chemically bonded together
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: 0
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 Rutherford’s alpha scattering experiment prove?
That atoms have a small dense nucleus with a positive charge
How did Bohr adapt the model of the atom?
He said electrons orbit the nucleus at specific distances
What did Chadwick’s work give evidence of?
That the nucleus also contained neutrons as well as protons
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
How were elemets arranged in the early attempts of the periodic table?
By atomic weight
How are elements in the periodic table arranged?
By atomic number
What are groups in the periodic table?
The columns, numbered 1, 2, 3, 4, 5, 6, 7, 0/8
What do you know about elements in the same group?
They have similar properties (reactions) as they have the same number of electrons in the outer shell
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 swap the order of some elements?
So they were in the same group as elements they had similar chemical properties with
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
How many electrons does calcium have?
20 (same as atomic number!)
How many electrons does silicon have?
14 (same as atomic number!)
How are the electrons in sulphur arranged?
2.8.6 (18 electrons total)
How are the electrons in magnesium arranged?
2.8.2 (12 electrons total)
How many electrons are in the outer shell of boron?
3 (it is in group 3!)
How many electrons are in the outer shell of phosphorous?
5 (it is in group 5!)
How many electrons are in the outer shell of sodium?
1 (it is in group 1!)
An element has three shells and three electrons in the outer shell. What element is it?
Aluminium (group 3, period 3
How many electrons are in the outer shell of Gallium?
3 (it is in group 3!)
How can solids be separated from liquids?
Filtration
What is crystallisation?
When a solution is heated until crystals start to form then left to cool until all the water evaporates
What does distillation do?
Separates mixture of liquids with different boiling points
What decides what element an atom is?
The number of protons. E.g. carbon always has 6 protons
Why do atoms have no charge?
They have the same number of protons and electrons
What is the approximate radius of an atoms
0.1nm (1x10-10m)
How big is the radius of the nucleus compared to that of the atom?
1/10000 the size (so 1x10-14m)
What is an isotope?
A version of the same element with a different mass. Or an atom with the same number of neutrons but a different number of protons.
How do you calculate the relative atomic mass of an isotope?
multiply the isotope mass by the abundance for each isotope, add them together and divide the answer by 100
What type of ions do metals form?
Positive ions as they lose electrons to get a full outer shell
What type of ions do non-metals form?
Negative ions as they gain electrons to get a full outer shell
In terms of electrons, what do group 1 (the alkali metals) elements have in common?
1 electron in the outer shell
In terms of electrons, what do group 7 elements (the halogens) have in common?
7 electrons in the outer shell
In terms of electrons, what do group 0 elements (the noble gases) have in common?
Full outer shell
What is more reactive, lithium or sodium?
Sodium
What is more reactive, chlorine or bromine?
Chlorine
Define inert
Unreactive
Explain why the noble gases are inert
They have full outer shells, so do not need to gain or lose electrons
What is a trend?
A pattern in properties
State the trend in the melting points of the alkali metals
Gets lower down the group
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
Balance the equation: Li + H₂O → LiOH + H₂
2Li + 2H₂ → 2LiOH + H₂
Balance the equation: K + H₂O → KOH + H₂
2K + H₂ → KOH + H₂
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 + I₂
Iodine is less reactive than bromine so cannot displace it
Balance the below 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
Explain why potassium is more reactive than lithium
More shells/electrons, less shielding (or weaker attraction from nucleus), easier to lose electrons
Explain why bromine is less reactive than chlorine
More shells/electrons, more shielding (or weaker attraction from nucleus), harder to gain electrons
Explain why sodium is less reactive than caesium
Fewer shells/electrons, less shielding (or stronger attraction from nucleus), harder to lose electrons
What is the equation for lithium reacting with oxygen?
4Li + O2 → 2Li2O
What is the equation for sodium reacting with chlorine?
2Na + Cl2 → 2NaCl
What are common properties of transition metals?
Many transition elements have ions with different charges, form coloured compounds and are useful as catalysts.
Name some common transition metals
Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickle (Ni), Copper (Cu)
How do transition metal properties differ from group 1 metals?
They have higher melting points, densities, strength and hardness and are also less reactive with oxygen, water and halogens
