Module 2 Flashcards
What are the definitions of:
RIM
RAM/Ar
RMM/RFM/Mr
RIM - Relative isotopic mass is mass of an isotope relative to 1/12th mass of an atom of carbon - 12 (p+n)
RAM/Ar - Weighted mean mass (of all isotopes of an element) relative to 1/12th mass of a carbon - 12 atom.
FMM/Mr: relative molecular mass
MFM: relative formula mass
What is relative molecular mass?
(Mr) The weighted mean mass of a molecule of a compound compared with 1/12th of the mass of an atom. carbon - 12.
23Na
11
What is the atomic mass no. and atomic no?
23 = atomic mass number number (A) 11 = atomic number (Z)
What is the atomic no. an element?
The no. protons in the nucleus of an atom
What is atomic mass measured in and how is carbon-12 used to work it out?
- Mass of carbon-12 isotope defined as exactly 12 atomic mass units (12u)
- Standard mass for atomic mass is 1u, mass of 1/12th of an atom of carbon-12
- 1m = mass of a proton/neutron
What is the mass no?
the sum of (no. nucleons) no. protons and neutrons in the nucleus - know as NUCLEON no.
What is an isotope?
Atoms of the same element. Have the same no. protons diff. no. neutrons.
Same atomic no. diff. mass no.
State the difference, if any, inthe chemical properties of isotopes of the same element.
Explain your answer
the chem properties are the same -they’re determined by the no./arrangement of electrons, which is the same
State any diff and similarities in the atomic structure of the isotopes of an element. State the diff, if any, in the chem of these isotopes. Explain
Diff isotopes of the same element have the same proton/atomic no. but differ int he no. neutrons (also mass no).
There’s no chem diff between isotopes of the same element as they have the same no electrons/electron configuration.
Definitions of:
a) element
b) compound
c) atom
d) molecule
e) symbol
a) 1 of the 100 or so simplest substances which can’t be broken down into simpler substances.
b) A substance made by chemical combination of s/more elements.
c) the smallest particle of an element that can take part in a chemical reaction
d) the smallest particle of a compound/element that can have a separate existence and has covalent bonds
e) a letter or pair of letters which represents 1 atom of an element
f) ion
g) formula
h) equation
f) an electrically charged atom/group of atoms. In chemical situations ions of 1 charge are usually balanced by ions of the opposite charge e.g. in a crystal/a solution
g) a group of symbols and usually no. which represent the no. atoms of each element in either 1 molecule of a compound/a formula unit. A giant structure. A formula can also be used to show the charge of an ion/the no. atoms and the charge. A compound ion ( 1with more than 1 atom)
h) a group of formulas and usually no. which represents the no. atoms and molecules involved in a chemical reaction.
What is the difference between cations and anions?
Cations: +ve ions
atoms with fewer electrons than protons
Anions: -ve ions
Atoms with more electrons than protons
Common ion symbols
1) hydrogen
2) sodium
3) silver
1) H+
2) Na+
3) Ag+
4) potassium
5) lithium
6) ammonium
4) K+
5) Li+
6) NH4+
7) barium
8) calcium
9) copper (II)
7) Ba2+
8) Ca2+
9) Cu2+
10) magnesium
11) zinc
12) lead
10) Mg2+
11) Zn2+
12) Pb2+
13) iron (II)
14) iron (III)
15) chloride
13) Fe2+
14) Fe3+
15) Al3+
16) bromide
17) fluoride
18) iodide
16) Cl-
17) F-
18) I-
19) HCO3
20) OH-
21) NO3-
19) hydrogencarbonate
20) hydroxide
21) nitrate
22) O2-
23) S2-
24) SO4 2-
22) oxide
23) sulphide
24) sulphate
25) CO3 2-
26) CN-
27) PO4 3-
Tetra means 4
25) carbonate
26) cyanide
27) phosphate
What is mass spectra used to identify?
The molecular mass of an organic compound and to gain further info. about its structure.
% abundances of the isotopes in a sample of an element.
How does a mass spectrometer work?
- A sample is placed in the mass spectrometer
- Sample is vapourised and then ionised to form =ve ions
- Ions are accelerated. heavier ions move more slowly and are more difficult to deflect than lighter ions, so the ions of each isotope are separated.
- ions are detected on a mass spectrum as a mass-to-charge ratio m/z. Each ion reaching the detector adds to the signal, so the greater the abundance, the larger the signal.
mass- to - charge m/z =
relative mass of ion/relative charge of ion
For 1 ion with 1 +ve charge, this ratio is equivalent to the relative isotopic mass, this recorded on the x-axis of a mass spectrum. Each peak show the % abundance of each isotope.
Waht are the binary compounds?
They contain 2 elements only.
- To name, use the name of the 1st element but change the ending of the second element to ide.
- for ionic compounds, the metal ion always comes first.
e. g. sodium and oxygen form sodium oxide
What are polyatomic ions?
An ion containing more than one element bonded together e.g. ammonium NH4+ nitrate NO3 carbonate CO3 2- phosphate PO4 3-
What are the 7 diatomic molecules?
H2 - Have N2 - no F2 - fear O2 - of I2 - ice Cl2 - cold Br2 - beer!
Give the oxidation numer and some exaples of the following combined elements. O F Mg2+, Ca2+ H Na+, K+ Cl-, Br-, I-
combined oxidation no. Examples
element
O -2 H2O, CaO
H +1 NH3, H2S
F -1 HF
Na+, K+ +1 NaCl, K2O
Mg2+, Ca2+ +2 MgCl2, CaO
Cl-, Br-, I- -1 HCl, KBr, CaI2
Special cases: Give the oxidation no. of these:
i) H in metal halides
ii) O in peroxides
iii) O bonded toF
i) -1 e.g. NaH, CaH2
ii) -1 e.g. H2O2
iii) +2 e.g. F2O
What is oxidation and reduction?
Oxidation - is addition of oxygen. - loss of electrons - increase in oxidation number Reduction: removal of oxygen. - gain of electrons -decrease in oxidation number IF one happens so must the other
Redox: loss/gain of oxygen
What is happening in the reaction?
CuO(s) + H2 (g) - Cu(s) + H2O (l)
Copper (11) oxide has lost oxygen it has therefore been reduced.
Hydrogen has gained oxygen it has therefore been oxidised.
Redox: electrons
What is happening in the reaction?
2Fe(s) + 3Cl2(g) - 2FeCl3 (s)
FeCl3 contains +ve and -ve ions, Fe3+ and Cl-.
-Iron loses electrons and is oxidised. 2Fe - 2Fe3+ + 6e-
- Chlorine gains electrons and is reduced. 3Cl2 + 6e- - 6Cl-
The electrons gained and lost balances:
2Fe in2Fe - each Fe looses 3e- - total of 6 electrons lost
6 Cl n 3Cl2 - each Cl gains le- - total of 6 electrons gained.
Redox: oxidation no.
What is happening in this reaction?
Cu(s) + 2AgNO3(aq) - 2Ag(aq) + Cu(NO3) (aq)
Cu(s) + 2AgNO3(Aq) - 2Ag(aq) + Cu(NO3)2(aq)
oxidisation-
reduction
+1 0 +2
The changes in ox.no. apply to each atom and the total changes in ox. no. balance.
1Cu in Cu - Cu increase by +2 - total increase = +2
2Ag in 2AgNO3 - each Ag decreases by -1 - total decrease = -2
Redox: reactions of acids:
What’s happening in these reactions?
A) Zn(s) + 2HCl(aq) - ZnCl2(aq) + H2(g)
B) 2Al(s) + 3H2SO4(aq) - Al2(SO4)3(aq) + 6H2(g)
Look at card for answer
What are shells?
- energy levels
- energy increases as shell no. increases
- shell no/energy level no. is called the
PRINCIPAL QUANTUM NUMBER, n
Sub Shells
sub shells max no. electrons
s 1.
p 2.
d 3.
f 4.
- 2
- 6
- 10
- 14
Describe how orbitals are filled up
- each at … orbital can hold max. 2 electrons
- electrons spin clockwise/anticlockwise
- electrons can only occupy the same orbtial if they’re opposite/paired spins
- filled in a certain order to produce the lowest energy arrangement possible
- filled in order of clockwise energy
- where there’s more than 1 orbital with the same energy, they’ve first filled singly by electrons (clockwise, anti, clockwise, clockwise)
- this keeps electrons in an atom as far apart as possible
Why is (Fe) in ‘d’ block of the periodic table?
It’s outermost electrons are in the ‘d’ orbitals OR because it’s highest energy level is (3) d.
Ionic properties
Solubility: Ionic lattice must be broken down. H2O molecules must attract and surround the ions. Insoluble in non-polar solvents. soluble in water.
Melting point: very high
Strength@ very brittle. any dislocation leads to layers moving and similarly charged ions being next to each other - repulsion
Electrical conductivity: don’t when solid - ions held strongly in lattice - conduct when molten/or in aqueous solution - ions are mobile
