Test 2 Flashcards
1
Q
Periodic Table
A
- Arrangement of known elements
- Organised in a way that HIGHLIGHTS period nature of they repeating properties
- Elements arranged into ROWS in order of INCREASING ATOMIC NUMBER
- Also arranged into COLUMNS according to SIMILAR CHEMICAL PROPERTIES
2
Q
Periods
A
- HORIZONTAL ROWS
- In order of INCREASING atomic number
- 7 Periods
3
Q
Groups
A
- VERTICAL COLUMNS
- In order of SIMILAR chemical properties
- 18 Groups
4
Q
Periodic Trends
A
- (LEFT TO RIGHT) Metallic to Non Metallic
- TOP TO BOTTOM in any GROUP the physical and chemical properties remain SIMILAR but INCREASE in metallic nature
5
Q
HALOGENS
A
- Reactive Non Metals
- Produce Ionic compounds with metals eg. CaCl2, AlBr3, NaF
- Group 17
6
Q
NOBLE GASES
A
- Non Metals
- Low chemical reactivity
- Group 18
7
Q
ALKALI METALS
A
- Group 1
- All soft low melting point metals
- React vigorously with water access to produce hydrogen gas
- Alkali Metals compounds are all ionic with the elements always forming +1 ions eg. LiCl, Na2S, K3PO4
8
Q
ALKALI EARTH METALS
A
- Group 2
- React strongly with acids producing hydrogen gas
- Also react with water, producing a metal hydroxide and hydrogen has
- Compounds are ionic, with metals always forming +2 e.g.. MgCl2, CaS and Sr3(PO4)2
9
Q
METAL ELEMENTS PROPERTIES
A
- Good conductors of electricity
- Good conductors of heat
- Malleable and ductile
- Shiny (when scratched)
- Solids at room temperature (except mercury)
10
Q
NON METAL ELEMENT PROPERTIES
A
- Poor conductors of electricity
- Poor conductors of heat
- Most are gases at room temperature
- Solid non metals are BRITTLE AND HARD
11
Q
QUANTUM MECHANICAL MODEL OF ELECTRON ARRANGEMENT
A
- Valence electrons on shells
- (2,8,8,18)
12
Q
VALENCE ELECTRONS
A
- Electrons on the outermost shell
13
Q
IONISATION
A
- Measure of how strongly an element holds onto its electrons
- Affects an elements tendency to form positive or negative ions
14
Q
IONISATION - ATOMS NUCLEAR CHARGE TREND
A
- Nuclear charge depends upon the number of protons in the nucleus
- Greater nuclear charger, greater number of electrons attracted STRONGLY to the nucleus
- Which means the ionisation energy increases with increasing nuclear charge
15
Q
IONISATION - DISTANCE BETWEEN NUCLEUS AND OUTERMOST ELECTRON (ATOMIC RADIUS)
A
- As atomic radius increases so the STRENGTH OF ATTRACTION between the nucleus and outer electron
- Ionisation energy decreases with increasing atomic radius
16
Q
IONISATION - SHIELDING BY INNER ELECTRON
A
- Each electron in the atom’s electron cloud REPELS each other electron
- The more electrons there are between the outer electron and the nucleus THE MORE EASILY the electron is removed
- Also means LOWER IONISATION ENERGY
17
Q
ATOMIC RADIUS
A
- The DECREASE in atomic radius that occurs for elements FURTHER RIGHT in the periodic table
- DECREASE IN ATOMIC RADIUS is due to the atomic increasing nuclear charge
- High nuclear charge (POSITIVE) increases the attraction of electrons which brings them CLOSER TO THE NUCLEUS resulting in a DECREASE IN ATOMIC RADIUS
- Atoms further to the right in a period show a DECREASE in in the size measured by their ATOMIC RADIUS
18
Q
INCREASING ATOMIC RADIUS
A
- Trend of INCREASING ATOMIC RADIUS down any group of the periodic table is due to the higher SHELL NUMBER OF ELECTRONS
- Higher number of shells are further away from the nuclear so atoms further down the group will have LARGE RADIUS
19
Q
ELECTRONEGATVITY
A
- The ability of an atom in a molecule to attract electrons to itself
- Caesium has the LOWEST electronegativity
- Fluorine has the HIGHEST electronegativity
- Non metals have the highest values of it, as these elements gain electrons to form negative ions
- Metals have low electronegativity
20
Q
METALLIC PROPERTIES
A
- LOW ionisation energy is essential is atoms want to form the positive ions required for METALLIC STRUCTURE (unique physical properties)
- Only found on the left side of the periodic table, as they have LOW IONISATION ENERGY
- Ionisation energies decreases down
- group elements metallic properties increase
21
Q
METALLIC - REDUCING AGENTS
A
- Lose electrons and become oxidised in substances like ACIDS, WATER AND OXYGEN
- Associated with low ionisation energy
22
Q
NON METAL PROPERTIES
A
- High hardness
- Brittleness
- High melting points
- High boiling points
- Semi conducting and non electrical conductivity
23
Q
UPPER RIGHT PERIODIC TABLE
A
- Highest ionisation
- Highest electronegativity
- Most valence electrons
24
Q
ELECTRON CONFIGURATON
A
- The electron configuration of an atom or ion shows the shells (1,2,3,4 …) containing electrons and the number of electrons in each of these shells
- Order in which electrons fill the available shells follows a general pattern where electrons fill the lowest numbered shells first
25
VALENCE ELECTRONS AND BONDING CAPACITY
- Strong relationship between the elements group number and its ionic bonding capacity
- Strong relationship between an elements covalent bonding capacity and its group number
26
ELECTRON CONFIGURATION AND ION FORMATION
- Atoms form ions by gaining or losing electrons
- Positive electrons have fewer electrons whilst negative ions have more electrons than the ORIGINAL ATOM
- Means electrons configurations of an atom and its ion must be different
- Usually the ion will have an electron configuration like that of the nearest noble gas
27
MASS SPECTROMETRE
- Analytical tool that can be used to determine relative molecular mass and molecular structure of complex organic compounds
- Its used to determine the relative atomic mass of the isotopes of an element
28
OPERATION OF MASS SPECTROMETER
- Vaporisation; of the sample to be analysed
- Ionisation; of the vapourised sample
- Acceleration; and separation of the resulting ions based on their mass to charge ratio
- Detection; or counting the number of each of the ions of different mass to charge ratio
29
HOW THE OPERATION WORKS
- Sample of chosen element is vaporised in a vacuum chamber then passed into the mass spectrometer
- Here is passes through A HIGH ENERGY ELECTRON BEAM where collisions within the beam cause the gaseous atoms to lose one of their electrons to form +1 ions
- Resulting ions are then accelerated by an ELECTRIC FIELD to form a high speed beam of positive ions directed through a STRONG MAGNETIC FIELD
- Individual ions become deflected by the field and move into circular paths of different radius
- Detector measures the intensity and radius of deflection of the ion beams
- Detector count is a measure of the isotope abundance
- Resulting data can be displayed as a mass spectrum of the sample
