Elements, compounds, mixtures and atoms Flashcards
What is an element?
a substance made up of one type of atom
What is a compound?
2 or more elements that are chemically combined
what is a mixture?
2 or more elements that are not chemically combined
what is a species?
anything - if you don’t know what it is
what is a particle?
a small bit of stuff
What is a molecule?
a small chemically combined collection of atoms like water (2 hydrogen, 1 oxygen)
What is a lattice?
a large structure of atoms that are chemically combined (that we can see)
What are atoms?
the simplest form an element can exist as
What are atoms made of?
3 subatomic particles: electrons, protons and neutrons.
What is the mass of an electron?
1/1836
What is the mass of a proton?
1
What is the mass of a neutron?
1
What is the charge of an electron?
negative
What is the charge of a proton?
positive
What is the charge of a neutron?
neutral (no charge)
On the periodic table which number is the atomic mass number?
the top one
On the periodic table which number is the atomic number?
the bottom one
what does the atomic mass number represent?
protons + neutrons
What does the atomic number represent?
number of protons
How do we know the number of electrons?
there has to be the same number of protons and electrons so the element doesn’t have an overall charge.
What do neutrons do?
hold the protons together to stop them repelling each other
How can you tell what period an atom is in?
how many shells it has
How can you tell which group an atom is in?
how many electrons it has on its outer shell
Why are the noble gases inert?
they have a full outer shell
