Chemistry - Atomic Structure (C2) Flashcards
Revision on Atomic structure and the C2 Structure
Define Atom
The smallest part of an element that can still be recognised as that element
Define Element
A substance made up of only one atom
Define Molecule
A substance made of two or more different atoms 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 relative charges of the subatomic particles
Protons +1, Neutrons 0, Electrons -1
State the masses of the subatomic particles
Protons 1, Neutrons 1, Electrons 0
How are the subatomic particles arranged in an atom?
Protons and Neutrons in the nucleus and electrons orbiting the outer shells.
What is the plum pudding model?
A ball of positive charge with negative electrons studded into it
What did Rutherford’s alpha scattering experiment prove?
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 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 other shells?
8
How were elements arranged in the early attempts of the periodic table?
By atomic weight
How are elements in the periodic table arranged?
By atomic number
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?
A charged particle
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?
An atom with the same number of protons but a different number of neutrons.
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 - Cations
What type of ions do non-metals form?
Negative ions as they gain electrons to get a full outer shell - Anions