Atoms and reactions 1

Question 1

What did Democritus come up with?

Answer 1

450BC
Suggested that if you divide matter enough times it eventually can no longer be divided as you would get a particle that wont split

Question 2

What was Daltons atomic theory?

Answer 2

Early 1800s
atoms are tiny particles that make up elements
atoms cannot be divided
atoms of a given element are the same
atoms of one element are different from other elements
- created table of atomic masses

Question 3

What did Joseph John Thomsen come up with?

Answer 3

1897-190
discovered that cathode rays were streams of particles called electrons 
they had a negative charge
could be deflected by a magnet and electric field 
had a small mass
this disproved Dalton and Democritus
the negative charge= positive charge 
- plum pudding model

Question 4

What was Ernest Rutherfords experiment?

Answer 4

1909-11
directed alpha particles towards a gold foil and measured the deflection
most of the particles did not deflect as expected
small percentage deflected at large angles
few deflected back to source
therefore
- positive charge and mass concentrated at centre in nucleus
- negative electrons orbit the nucleus
- most of the volume is between electrons and nucleus
- overall positive = negative charge

Question 5

What did Niel Bohr come up with?

Answer 5

1913
altered Rutherford’s experiment and stated that electrons followed paths this explained
- spectral lines seen on emission spectra
- energy of electrons at different stands from nucleus

Question 6

What did Henry Mosely come up with?

Answer 6

1913

discovered the link between x ray frequencies and elements atomic number

Question 7

What did Rutherford discovery of the proton explain?

Answer 7

1918
- discovered the proton this explained how the atomic number was linked to x ray frequencies
atomic number=proton number

Question 8

What did Louis de Broglie suggest?

Answer 8

1923

particles could have the nature of a wave

Question 9

What did Erwin Schrodinger suggest?

Answer 9

1926
electrons had wave like properties in an atoms
atomic orbitals

Question 10

What did James Chadwick discover?

Answer 10

1932, neutron
he obsereve a new type of radiation emitted from elements and showed it was made out of neutrons which had no charge and was the same mass as a proton

Question 11

The modern atom

Answer 11

protons and neutrons are made out of quarks

Question 12

What is the relative mass and charge of a proton?

Answer 12

1

1+

Question 13

What is the relative mass and charge of a neutron?

Answer 13

1

0

Question 14

What is the relative mass and charge of an electron?

Answer 14

1/2000

1-

Question 15

What do isotopes have?

Answer 15

different mass number due to different number of neutrons

same number of protons and electrons therefore same atomic number

Question 16

Why do isotopes react in the same way?

Answer 16

chemical reaction involve electrons and they have the same number of electrons, neutrons do not affect chemical reactions

Question 17

What are isotope properties?

Answer 17

chemical = same
physical = different due to different masses involved

Question 18

What causes an ion?

Answer 18

when atoms lose or gain electrons and no longer have an equal number of protons and electrons

Question 19

How do you work out charge?

Answer 19

proton-electron

Question 20

What is the international standard for measurement of relative mass?

Answer 20

carbon-12

Question 21

for an isotope what is the relative isotopic mass the same as?

Answer 21

mass number

Question 22

why do you use the term weighted mass?

Answer 22

most elements contain a mixture of isotopes each in a different amount and different mass

Question 23

What does the overall mass depend on?

Answer 23

the percentage abundance, relative mass of the isotope

Question 24

How do you get the relative molecular mass? (simple molecules)

Answer 24

add together the relative atomic masses

Question 25

How do you get the relative formula mass?(giant molecules)

Answer 25

add together the relative atomic masses

Question 26

How do chemists count atoms?

Answer 26

the use a quantity called amount of substance for counting atoms

Question 27

What is the amount of substance based on?

Answer 27

it is based on a standard count of atoms called the Avogadro constant this is the number of atoms per mole of the carbon-12 isotope

Question 28

the mass of one mole….

Answer 28

is the relative atomic mass in grams

Question 29

What is the empirical formula?

Answer 29

The simplest whole-number ratio of atoms of each element present in a compound

Question 30

What is the empirical formula used for?

Answer 30

it is used for giant structures such as ionic compounds and giant covalent compounds

Question 31

What is the molecular formula used for?

Answer 31

its used for compounds that are simple molecules

Question 32

Definition of the molecular formula ?

Answer 32

the number and type of atoms of each element present in a molecule

Question 33

How do you work out the molecular formula?

Answer 33

use the empirical formula, must be the same as or whole number

Question 34

What do we do with by-products?

Answer 34

considered waste and have to be disposed of they have potential environmental harm and waste of valuable resources
they are usually sold or used elsewhere

Question 35

What does atom economy describe?

Answer 35

it describes the efficiency of a reaction in terms of all the atoms involved

Question 36

What is the equation of atom economy?

Answer 36

molecular mass of desired product/sum of molecular masses of all products x 100%

Question 37

How can atom economy benefit society?

Answer 37

reduce the amount of waste products and make it sustainable

Question 38

What’s the difference between atom economy and percentage yield?

Answer 38

percentage yield tells us the efficiency with which reactants are converted into products whereas atom economy tells us the proportion of desired products compared with all products formed

Question 39

What is a addition reactions?

What is the atom economy of addition reactions?

Answer 39

2 or more reactants join together

100%

Question 40

What is a substitution reaction?

What is the atom economy of substitution reactions?

Answer 40

1 or more atoms or molecules swapping places with another

less than 100%

Question 41

What is a elimination reaction?

What is the atom economy of an elimination reaction?

Answer 41

removal of a small molecule (usually water) from another molecule
less than 100%

Question 42

what do atoms of metals in group 1-13 do? (balancing charges)

Answer 42

loose electrons and form positive ions

Question 43

what do the transition metals do (balancing reactions)

Answer 43

e.g. nickel(11) has 2+ charge

Question 44

what happens in group 15-17

Answer 44

gain electrons and form negative ions

Question 45

what happens to Be, B, C, Si

Answer 45

do not usually form ions as it requires too much energy to transfer the outer shell electrons to form ions

Question 46

what are molecular ions?

Answer 46

groups of covalently bonded atoms that can lose or gain electrons to form ions

Question 47

what ions have a 1+ charge

Answer 47

ammonium NH4+

Ag+

Question 48

What ions have a 1- charge

Answer 48

hydroxide - OH -

nitrate - NO3-

Question 49

What ions have a 2- charge

Answer 49

carbonate CO32-

sulfate SO42-

Question 50

How can you predict formulae?

Answer 50

overall charges must be o

Question 51

What ions have a 2+ charge

Answer 51

Zn2+

Question 52

define relative isotopic mass

Answer 52

this is the mass of an atom of an isotope compared with 1/12 the mass of an atom of carbon-12

Question 53

Define relative atomic mass

Answer 53

this is the weighted mean mass of an atom of an element compared with 1/12 the mass of an atom of carbon -12

Question 54

Uses of mass spectrometry

Answer 54

• determination of relative isotopic mass and the relative abundances of the isotope
• calculation of the relative atomic mas of an element from the relative abundances of its isotopes