C1 Flashcards
explanations about atoms started around?
400B.C
in 1803, what scientist began to develop the atom in detail
what did his model describe
John Dalton
his model described an atom as a “billiard ball”that cannot be divided
in 1897, a scientist made what discovery
J.J Thomson discovered the electron
what did Thomson describe the atom as?
A “plum pudding” model - negative electrons embedded in a ball of positive charge
in 1909, 3 scientist made what discovery after an experiment
Geiger, Marsden and Ernest Rutherford proposed that atoms have a nucleus
1911, Rutherford created what model of the atom and what was it described as
The nuclear model
a positively charged nucleus in the centre where most of the atom mass was concentrated
1913, What scientist agreed/complemented Rutherford 1911 discovery and how
Niels Bohr
he said the electrons orbited the positively charged nucleus at specific distances -
he said a fixed amount of energy was required for electrons to move from one orbit to the next
when was the “proton” first used/named
1920
when was the neutron discovered and by who
1932 by James Chadwick
what is the nucleus made up of
what orbits this nucleus
protons and neutrons
electrons
what is the atomic number
the number of protons in an atom
what is the mass number
the total number of protons and neutrons in an atom
why is there an equal amount of protons and electrons in an atom
because they are oppositely charged and the atom must be neutral(for it to not be an ion) they must cancel each other out
give an example of working out the number of protons and neutrons with the mass number
23
11 C
atomic number=11 mass number=23 23-11=12 12 neutrons 11 protons and electrons
what are isotopes
a form of an atom with a different mass number due to a change in neutrons
why can isotopes not be a change in electrons or protons
isotopes are a change in mass number-electrons have no mass
because it will change the charge therefore it is no longer the same atom(change in protons) or it becomes an ion(change in electrons)
what is the equation for relative atomic mass
Ar= (mass of first isotope x % of first isotope) + (mass of 2nd isotope x % of 2nd isotope)
_______________________________________________________________
100
Name the group 7 elements
What are they called
(F)Fluorine, (Cl)Chlorine, (Br) Bromine, (I) Iodine, (At)Astaline
Halogens
what are halogens
group 7
non metals that exist as pairs of atoms
(F2, Br2, Cl2, I2)
how do you balance an equation
balance MG+O2-> MGO
have an equal amount of products as reactants
2MG+O2->2MGO
what is the relationship between atomic mass and relative molecular mass
RMM is double the AM
as molecular mass increases, what else increases?
BP and MP
if MP and BP are both negative what is the state of the halogen at room temp?
if MP is negative and BP is positive(vice versa)?
if MP and BP are both positive?
Gas
Liquid
Solid
as you go down group 7 how does the reactivity change?
it decreases
