Topic 2: Gases atomic structure, formulae and equations Flashcards
do pure substance have a fixed or range of melting or boiling points
pure substances have a fixed melting and boiling point
do mixtures have a fixed melting and boiling point or range of melting and boiling points
mixtures may melt or boil over a range of temeratures
what is an atom made up of
an atome consists of a central nucleus, composed of neutrons and protons, surrounded by electrons, orbiting in shells
what are the properties, relative mass and charge of protons
protons are heavy and positively charged
relative mass: 1
relative charge:+1
what are the properties, relative mass and charge of neutrons
neutrons are heavy and neutral
relative mass: 1
relative charge: 0
what are the properties, relative mass and charge of electrons
electrons have hardly any mass and are negatively charged.
relative mass: 0.0005
relative charge: -1
what is an atomic number
an atomic number tells you how many protons there are
what is a mass number
-the mass number is the total number of protons and neutron is the atom.
-to get the number of neutrons, subtract the atomic number from the mass number
what is an isotope?
isotopes are different atomic forms of the same element, which have a the same number of protons but different number of neutrons.
how do you deduce the electronic configuration of the first 20 elements in from their position in the periodic table
the first shell is 2 electrons, the rest are 8
- the amount of electrons fill up the shells from the centre out.
how does the electronic configuration of a main group element relate to its position in the periodic table
the group number is the number of electrons in the outer shell of an atom.
why do element is the same group have similar properties?
they have the same amount of electrons in their outer shells so they react similarly.
does the total mass of reactants change after a reaction
the total mass of reactant and no atoms are made or destroyed.
