1.5 atomic structure and periodic table Flashcards Preview

Chemistry AS (2015) > 1.5 atomic structure and periodic table > Flashcards

Flashcards in 1.5 atomic structure and periodic table Deck (16):

a What is relative atomic mass?

the mass of an atom averaged over its isotopes relative to 1/12 of a C-12 atom


a What is relative isotopic mass?

the mass of an isotope relative to 1/12 of a C-12 atom


b What happens within a mass spectrometer?

electron gun knocks electrons out of their shells, creating positive ions
these are accelerated using a negatively-charged plate
a magnetic field deflects them so that they hit detectors at the end


b How are mass spectrometers useful?

more massive particles are deflected less, so the RAM can be found; this allows for one to deduce isotopic composition of an element or RMM of a compound


d Define the term 'first ionisation energy'.

the enthalpy required to form one mole of unipositive gaseous ions from the element in a monatomic gaseous state


g Give the shape of and no. of electrons within
a) an s subshell
b) a p subshell

a) spherical, 2
b) three figures of eight on the xyz planes, 6


g In what order do shells fill up?

1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p...


g Describe how the p shell fills up.

first e- goes in one 8-shaped orbital
second and third go in the other two
thence, electrons pair up


h Why is it easier to remove electrons from 4s than 2s?

further from nucleus: less attraction
electron shells between it and nucleus: more repulsion (shielding effect)


h Why is it easier to remove an electron from a p subshell if >3 are present (as opposed to <4)

electrons paired up; repulsive effect within orbital


h What happens when there are 4 or 9 electrons in a d subshell?

one electron is removed from the s subshell below it


i What properties do elements within s/p/d blocks have?

their outermost electron is in an s/p/d subshell


j What is a periodic property?

a quantity for which there is a trend across the periodic table


j What is the trend for atomic radius and why?

increases towards the top-right
going right -> nuclear charge increases
going up -> number of shells decreases


ki What is the trend for melting temperatures in groups 2 + 3 and why?

ionic radius increases
greater distance between nuclei and delocalised electrons
less attraction


kii What is the trend for ionisaiton energy along a period and why?

general increase but drops at the start of every new subshell due to distance + shielding, and midway through filling subshells due to repulsion between paired electrons