Periodic Table Flashcards
General characteristics of Groups
(Vertical Column of elements -top to bottom-)
- Elements in the same group have the same number of valence electrons. (specify how many)
- Elements in the same group exhibit similar chemical reactions.
- Forms similar chemical formulas
General characteristics of elements in periods
(Horizontal row, Left to Right)
- Elements in the same period have atoms with the same number of electrons shells (specify how many)
- The number of electron shells is shown in the eletronic configuration (no. Of sets)
Metals;
+ charge
Tendency to lose valence electrons
Basic oxides
Non metals;
- charge
Tendency to gain valence electrons
Acidic oxide
General trend down groups
- number of electron shell increases down the group
- Group 14,15,16 changes from non-metals (top) to metals (bottom) -metallic properties increases
General trend across periods
- Number of valence electrons increases by 1 for each consecutive element across the period.
- Properties change from; metals -> metalloids -> non metal
Metallic properties decreases across the period. ( I.e. tendency to lose valence electrons decreases across the period.
Physical properties of group 1 Alkali metals
-shiny silver grey appearance
-soft metals (can be easily compressed - malleable/ cut by a knife)
-low melting points (compared to other metals)
-Low density (Linak)
-good conductors of heat & electricity
Chemical properties of group 1 alkali metals
Known as the reactive metals.
-reacts rapidly/readily/vigorously with water to form alkali & hydrogen gas (exothermic reactions)
-reacts vigorously with group 17
-high tendency to lose its 1 valence electron to form a positive ion
How are group 1 alkali metals stored?
Stored in mineral oil as they oxidise readily in air to form a layer of oxide on its surface.
Physical properties of group 17 halogens
-coloured substances
-low melting & boiling point (non-metals)
-poor conductors of heat & electricity (non-metals)
-brittle (I.e. iodine crystals)
Chemical properties of groups 17 halogens
Known as the non-reactive metals
-combines with hydrogen to form acidic substances (I.e. H2 + CL2 -> 2HCL)
-combines with metals to form salts ( Halogen -> salt former )
-reacts vigorously with group 1 metals
-High tendency to gain an electron to form a negative ion
-exists as diatomic atoms at room temperature
Properties of group 18 noble gases
-chemically unreactive gases
-atoms in group 18 do not form compounds with other elements as they have a completely filled valence shell.
Hence, these elements do not gain, lose or share electrons with atoms of other elements.
-exists as a monoatomic atom at room temperature
Trends down group 1
-elements get softer (more malleable) down the group (hardness decreases)
-density increases (with exception of potassium)
-melting & boiling point decreases
-atomic radius increases
-reactivity increases
Observation of 2Li + 2H2O
2LiOH+H2
Reacts readily with water
Fizzes & floats on the surface of water
Effervescence observed
Observation of 2Na + 2H2O
2NaOH + H2
Reacts vigorously with water
Fizzes rapidly on the surface of water as it melts to form a white ball. May explode with an orange flame.
Observation of 2K + 2H2O
2KOH + H2
Reacts explosively with water
Explode when in contact with water; fizzes as it explodes and burns with a Lilac flame
Trends down group 17
-Density increases
-Melting & Boiling point increases
-colour intensity of element increases
-Reactivity decreases
Displacement reactions & observations
-Principle of displacement: more reactive element displacing less reactive element from its compound.
-Displacement reactions are redox reactions
-Concept: more reactive halogen will displace the less reactive halide from its salt solution.
Colour of Florine when dissolved in water
Colourless
Colour of Chlorine dissolved in water
Pale yellow
Colour of bromine dissolved in water
Orange
Colour of Iodine dissolved in water
Brown
Describe what happens when chlorine displaces bromine
Chlorine is more reactive than bromine, chlorine will displace bromide ions from its salt solution
State and explain what you would observe when a jet of chlorine gas is aimed filter paper soaked in solution of potassium iodide
Colourless filter paper turns brown.
Chlorine is more reactive than iodine. Chlorine will displace iodine from potassium iodide
State the electronic structures of lithium & sodium and explain why they are in the same group of periodic table
Sodium is 2,8,1
Lithium is 2,1
They have same number of 1 valence electrons
Sodium placed into beaker with water & potassium in another.
Describe 2 similarities & 1 difference in observation
Similarities:
-effervescence observed, colour flame observed
Difference:
-Potassium shows a more vigorous reaction with water compared to sodium
