Atomic structure and the periodic table, C1 Flashcards
what is in the middle of an atom
the nucleus
what does the nucleus contain
protons and neutrons
do nuclei have a positive or negative charge
why?
positive charge
because of the protons
the relative mass of a proton
1
the relative mass of a neutron
1
the relative mass of an electron
very small (often taken as 0) virtually no mass
charge of a proton
+1, positive
charge of a neutron
no charge, neutral
charge of an electron
-1, negative
why are atoms neutral (have no charge overall)
same number of protons as electrons
why do ions have an overall charge
give example
the number of protons doesn’t equal the number of electrons
for example, an ion with a 2- charge has two more electrons than protons
how is an ion formed
when an atom loses or gains an electron
what does the atomic number tell you
is it the top or bottom of the nuclear symbol
how many protons there are
bottom
what does the mass number tell you
is it top or bottom of the nuclear symbol
total number of protons and neutrons in the atom
top
how do you work out the number of neutrons in a nuclear symbol
mass number - atomic number
what is an element made from
atoms that all have the same number of protons in their nucleus
isotopes
same number of protons and electrons but a different number of neutrons
what similarities do elements of the same group have about their shells
they all have the same number of shells
TRUE OR FALSE
elements in the same group all have the same number of electrons in their outer shell
true
DELETE
false
what do you call an atom with an incomplete outer shell
unstable
how do you write an ion when the atom has lost an electron
+
how do you write an ion when the atom has gained an electron
-
do metals or non-metals always lose electrons
metals
non-metals always gain electrons
what did james chadwick discover in 1932
neutrons
how would a lithium atom form a lithium ion
when a lithium atom loses one electron from its outer shell
why are electrons and protons attracted to each other
opposites attract
who’s and what theory did JJ Thompson prove wrong in 1897
John Dalton’s theory that described atoms as solid spheres and that different spheres made up different elements
what was the plum pudding model
JJ Thompson discovered that atoms weren’t solid spheres but instead must contain even smaller negatively charged particles, electrons
when and who disproved the plum pudding model
ernest rutherford in 1909
what did ernest rutherford discover using what experiment
- what was it called
- that there must be a nucleus in the centre of the atom as some particles were deflected when thrown
- alpha particle scattering experiment
what is Bohr’s nuclear model
the discovery that electrons orbit the nucleus in fixed shells
does the periodic table show compounds
no, only individual elements
how many elements have been discovered
approximately 100
are all the atoms in an element the same
yes, bar isotopes
what does the plum pudding model show
that atoms contained negative particles (electrons) embedded in a ball of positive charge
