2.1 Matter Flashcards
What do elements consist of?
1 atom
What do compounds consist of?
Molecules (groups of elements)
What does an atom have?
Nucleus, proton and neutron.
What does the neucleus consist of?
Protons and neutrons.
What is important about protons and neutrons despite one being negative and one positive?
The have the same mass.
What is the atomic number?
Number of protons in the nucleus and is how an atom is identified.
What is the mass number?
The number of protons and neutrons in the nucleus.
Which way are orbiting electrons charged?
Negatively.
What is the mass of an electron vs a proton?
1/1845 however they hold the same electrical charge.
How does an atom become neutral?
Having the same number of electrons and protons.
What is the simplest atom?
Hydrogen because it has one proton and one electron.
How are the layers/shells of electrons labelled?
Alphabetically, starting with K at the closest shell to the nucleus.
How is the maximum number of electrons per shell governed?
Using the formula 2n² where n is the numerical number of the shell.
What is the valence electron?
The outermost electron in orbit.
When atoms are close together what are the forces between them?
Electromagnetic in nature.
What is the result of the electromagnetic force between atoms?
When they are a certain distance apart there is zero force, when they are closer they repel, when they are further away they attract.
In a solid substance what do the molecules do?
Vibrate about their zero positions, alternately attracting and repelling.
What structure do all true solids have?
Chrystal-line, where the atoms are arranged in a lattice.
In a liquid what do the molecules do?
They vibrate similar to a solid however they can freely move among one another.
In a gas substance what do the molecules do?
They are much further apart and move at high velocities colliding with one another.
Why is a gas completely free to expand to the container it is in?
Because the molecules are so far apart that there are no intermolecular forces to either repel or attract.
The word heat is the name given to energy in the process of what?
Energy transfer from one body to another as a result of the temp difference.
What happens to heat once it has been transferred to a body or substance?
It ceases to be heat and instead becomes internal molecular energy.
How does a solid become liquid?
The molecules gain energy vibrate over bigger distances and can move freely becoming liquid state.
What is absolute zero?
Theoretical temperature at which the movement of atoms in a solid become their lowest.
What temp is absolute zero?
0 kelvin
-273 degrees C.
What is matter?
A substance of which a physical object is composed of as long as the weight and dimensions can be measured.
Where can you find all the elements or substances from which all matter is made up?
Periodic table.
What is the mass of proton and neutron?
1.67 x10 ¯²⁷
What speed does an electron travel at due to its extremely small mass?
Speed of light
What is the next simplest atom after hydrogen and why?
Helium, it has two protons, two neutrons and two electrons.
How is each atom identifiable?
By the number of protons.
When are atoms most stable and less reactive?
When their valence is full.
Atoms that have fewer than half their valence electrons easily carry moving electrons and are known as what?
Conductors
Atoms that have more than half their valence electrons are known as?
Insulators
What is an isoptope?
An element that exists in a different variation, for example if a hydrogen atom gains an neutron then it becomes Deuterium.
What are the two isotopes of carbon?
Carbon-12 and carbon-14, they are named after their mass numbers.
In an atomic letter what do the upper and lower numbers refer too?
The upper is the protons (atomic number), and the lower is the atomic mass.
What is the atomic mass?
The number of protons and neutrons in the nucleus.
What is an ion?
An atom or group of atoms with a positive or negative charge.
How do ions form?
When an atom lose or gain electrons to obtain a full valence.
What is the process through which ions formed called?
Ionisation.
What is a negative ion called?
Anion
What is a positive ion called?
Cation
What is a molecule?
A pure substance which results when two or more atoms share electrons e.g. O2
What is chemical bonding?
The act of bonding molecules to form a substance.
What is covalent bonding?
Two atoms share one or more electrons to form molecules.
Where does covalent bonding take place?
Usually takes place between two non-metallic elements in a molecule.
What is ionic bonding?
One atom transfers electrons to another atom. The atom losing electrons forms a positive ion and normally metallic. The atom that gains becomes negative and normally non-metallic.
What is a chemical compound?
A substance made up of two or more elements which join together in a chemical reaction making them difficult to seperate.
How many elements are there in the periodic table?
118
If the valence shell is full the what is the atom said to be?
Stable.
If the valence shell is less than half full what will the material be?
Conductive.
If the valence shell is more than half full what will the material be?
An insulator.
What 3 examples of mixtures are there?
Solutions (sea water)
Suspensions (sand in water)
Colloids (clouds)
If atmospheric pressure is lower is it easier or harder to boil water?
Easier.
What is sublimation?
Solid to gas without passing through liquid phase.
What is deposition?
Gas to solid without passing through liquid.
How many electrons does titanium have?
22
How do you work out the valency?
If the outer shell is less than 4 the number is its valency, if its more then its 8- number = valency.
What form of heat is used to turn into a liquid?
Heat of fusion.
What is the difference between synthesis and analysis?
Synthesis is the making of a compound, analysis is the breaking down.
