atomic structure

Question 1

nucleus has an overall charge that is

Answer 1

positive

Question 2

charge on electrons

Answer 2

negative

Question 3

subatomic particals are:

Answer 3

the partacles an element is made up of

Question 4

relative charge of and mass of proton

Answer 4

+1 1

Question 5

relative charge of and mass of neutron

Answer 5

0 1

Question 6

electron

Answer 6

-1 1/1836

Question 7

atomic number

Answer 7

number of protons

Question 8

mass number

Answer 8

total number of protons and neutrons in the nucleus

Question 9

isotopes have ____ chemical properties but _______ physical properties

Answer 9

isotopes have similar chemical properties but different physical properties

Question 10

why isotopes of the same element have the same chemical properties

Answer 10

same number of electrons in outer shell

Question 11

why differentr physical properties

Answer 11

different number of neutrons adds mass which changes these eg. lighter gas molecules collect closer to the centre

Question 12

symbol for an isotope

Answer 12

chemical word foolowed by dash then mass number eg. carbon - 12

Question 13

relative isotopic mass =

Answer 13

mass of an isotope relative to the mass of 1/12 th of an a tom of carbon - 12

Question 14

relative atomic mass =

Answer 14

weighted average mass of an atom relative to 1/12 of the mass of an atom of carbon - 12

Question 15

Relative formular mass =

Answer 15

total mass of a substance

Question 16

relative atomic mass calculation

Answer 16

relative abundance(isotope1) x mass(isotope1) + (relative abundance (isotope2) x mass (isotope2)
/100

Question 17

predicting mass spectra

Answer 17

example chlorine :
exists as cl - 35 and cl - 37

therefore has 2 molecular ion peaks
ratio of peak heights is 3:1 as cl - 35 is 3x more abundant

will also have 3 other peaks -

35 + 35 = 70
37+37 = 74
35+37 = 74

ratio of peaks is 9:6:1

this is deduced by using the probability of each chlorine atom.

eg. 3/4 x 3/4 = 9/16
1/4 x 1/4 = 1/16
3/4 x 1/4 = 3/16 - yet this doubles as there is two of 35 = 37 when done in a grid

Question 18

what happens in mass specxtrometer

Answer 18

vaporised molecules are bombarded with a beam of high speed electrons

Question 19

knock off electrons form

Answer 19

molecular ions

molecule ——> molecule + electron

during electron bombardment

Question 20

peak with highes mass/charge (M+) =

Answer 20

molecular ion peak which gives info about the molecular mass of a compound

Question 21

M+1 peak =

Answer 21

smaller peak due to the abundance of isotopes with one extra mass

height of this peak depends on how many of the atom are present in that molecule

the more atoms the larger the peak.