End Of Year Revision Year 9 Flashcards
What happens when a solid becomes a liquid
The particles heat up and get more energy from there surroundings so they break the bonds holding them in place and move around becoming a liquid
What happens when a substance freezes
The liquid becomes a solid because the particles cool down and loose energy because they transfer it into the environment to equalise the temperature so they stop moving around and vibrate on the spot creating a solid.
What is sublimation
Sublimation is when a solid turns directly into a gas skipping the liquid phase e.g. when iodine crystals turn into vapour.
What is deposition
Deposition is when a gas turns directly into a solid skipping the liquid phase e.g. like when frost turns into ice
What kind of melting point does a pure substance have
A sharp one
How can we use boiling points to identify unknown substances
If the substance has a sharp boiling point we can tell it is a pure substance and match up the substance to its boiling point. If it doesn’t have a sharp boiling point we can tell it is not pure
What is an element
An element has two or more of the same atom chemically joined together
What is an compound
A compound is a substance that has two or more different atoms chemically joined together
What is a mixture
A mixture is a substance that is made up of different atoms and elements that are not chemically fused together e.g. paint
What subatomic particles are atoms made up of.
Protons
Neutrons
Electrons
What are the mass and charge of the subatomic particles
Subatomic particle. Mass. Charge.
proton. 1. +1
Neutron. 1. 0
Electron. 0. -1
What are periods
Periods are the horizontal rows in the periodic table and tell you how many electron shells there are e.g. all the elements in period 3 will have 3 electron shells
What are groups
Groups are the vertical columns in the periodic table and tell you how many electrons are in the outer shell
What are valance electrons
Electrons on the outermost shell
How is the periodic table arranged
The periodic table is arranged by atomic number and is divided into groups and periods depending on how many shells are in an element and how many valance electrons there are
