C1 Atomic Structure and the Periodic Table Flashcards
What is an element?
a substance containing only one type of atom.
What is a compound?
a substance containing two or more different atoms chemically bonded.
What is the conservation of mass?
Atoms can neither be created or destroyed in a reaction.
What is a mixture?
consists of different substances not chemically bonded.
What are the separation techniques?
Filtration, Evaporation, Distillation, Fractional Distillation and Chromatography.
What are the properties of solids?
Particles in regular arrangement and vibrate about fixed positions.
Cannot be compressed.
What are the properties of a liquid?
Particles have no regular arrangement and are able to most past each other.
Cannot be compressed.
What are the properties of a gas?
Particles are far apart, move randomly at fast speeds.
Can be compressed.
What does Aqueous mean?
Something that is dissolved in water.
What did JJ Thomson discover?
He made the ‘plum pudding’ model which states that an atom is a ball of positive charge which is embedded with negative things.
What did Ernest Rutherford discover?
He discovered that the nucleus was small and positively charges. He found that most alpha particles went straight through a gold ‘leaf’; very few deflected back.
What did Neils Bohr discover?
He discovered that electrons exist in ‘shells’.
What did James Chadwick discover?
The nucleus must contain neutrons as well as protons.
What is an atomic number?
The number of protons in a nucleus.
What is the mass number?
The number of protons and neutrons in a nucleus.
What is an isotope?
The same element with the same amount of protons but a different amount of neutrons.
How do you work out average mass?
average mass = (total mass of 100 atoms) / 100
How did Dimitri Mendeleev create a periodic table?
Grouped elements by their properties. Left gaps for elements to be discovered in the future.
What is the grouping of the periodic table?
Left of ‘staircase’ - metals
Right of the ‘staircase’ - non-metals
What happens with group 1?
These are known as Alkali metals and have 1 electron in their outer shell so have a + charge when losing their outer shell. They get more reactive as you go down the group since their most outer electron is getting further away from the nucleus.
What happens with group 7?
These are known as Halogens and they form - ions as they gain an electron to fill their outer shell. They get less reactive down the group and boiling points increase.
What happens with group 0/8?
They are very unreactive since they already have an outer shell.
