Atomic Structure Flashcards
how many elements are there
118
how are the elements get arranged in groups
according to how many are in the outer most energy level
describe alkali metals
VERY reactive
soft
react with water
react with oxygen
describe transition metals
hard and dense
less reactive
used in catalysts
form coloured compounds
describe the halogens
diatomic elements
all toxic
chlorine used to sterilise swimming pools
describe nobel gases
least reactive
DO NOT REACT AT ALL
what is the centre of the atom called and what does it contain what’s its charge
its called the nucleus and contains protons and neutrons and is positively charged
what circles round the atom and what is its charge
the electrons circle round and are negatively charged
how is the atom neutral
its neutral because the number of positively charged protons cancels out the negatively charged electrons
what is the top number mean in nuclide notation
the top number is the mass number
what is the bottom number in nuclide notation and what does it represent
its the atomic number and represents the number of protons and electrons
what are isotopes
isotopes are atoms of the same element have the same atomic number but diffrent mass numbers
how do you calculate the relative atomic mass
(mass of isotopes 1 x %) + (mass isotopes 2 x %) divide by 100
what is the electron arrangement for sodium
2,8,1
why do elements in a group have similar chemical properties
because they have the same number of outer electrons
what is an ion
an ion is where an atom gains or loses electrons and charged particles which are ions are formed
what happens if an atom gains an electron
it becomes a negatively charged ion
what happens if an atom loses an electron
it becomes a positively charged ion.
do metals gain or lose electrons
do non-metals gain or lose electrons
metals always lose to become positively charged
non-metals always gain to become negativly charged
why do atoms lose or gain electrons
its so they achieve a full outer most energy level.
what are atoms joined by
atoms can be joined by bonds
if the bonded atoms are the same what is it
its a molecule of an element