periodic table Flashcards
what are metalloids
elements close to the staircase can have metallic and non metallic properties
physical properties of Group I elements (alkali metals)
- low density and melting point
- good conductors of heat and electricity due to free mobile electrons
- are silvery and shiny solids
- softer than most other metals
as we move down Group I (alkali metals) mp ___
melting point decreases decreases as:
- as the atomic size increases down the group
- the valence electron is further away from the positive nucleus
- hence there is weaker electrostatic forces of attraction between the fixed positive ions and the sea of mobile electrons
- hence less energy is needed to overcome these forces of attraction and the melting point decreases
density generally increases
metals become softer due to the decrease in mp
chemical properties of Group I (alkali metals)
- highly reactive metals as they have strong tendency to give away their one valance electron to achieve stable electronic configuration with full electron shells
- reacts violently with oxygen
catch fire and burn wit characteristic flame colours to form white oxides:
- lithium flame: red
- sodium flame: yellow/orange
- potassium flame: lilac
- to avoid getting corroded, these metals are stored under oil to prevent group I metals from coming into contact with oxygen and water vapour in air
- they lose one valance electron to form ions with a charge of 1+ and form ionic compounds
- they react vigorously with water to produce hydrogen gas and an alkaline hydroxide of the metal
as we move down Group I (alkali metals) the metals become ___ reactive
more reactive and become stronger reducing agents
- the atoms become larger as the number of valance shells increases
- the electrostatic forces of attraction between the valance electron and positive nucleus gets weaker as the valance electron becomes further away from the positive nucleus
- the valance electron is held less strongly and is more easily so that group I metals become more reactive/ stringer reducing agent
metals reaction with water
lithium: reacts quickly
sodium: reacts vigorously, catches fire sometimes (yellow flame)
potassium: explodes in water, catches fire (lilac flame)
rubidium: reacts more explosively in water than potassium
halogens
non metals and exist as diatomic covalent molecules
physical properties of halogens
- low mp bp
- unable to conduct electricity in any states as there are no free mobile ions or electrons
as we move down Groupon VII mp bp ___
mp and bp increases
- the molecules are getting bigger
- there is strong intermolecular forces of attraction
- more energy is needed to overcome theses forces of attraction
colour of the elements become darker
density increases
chemical properties of halogens
- most reactive non metals
- has a strong tendency to gain 1 electron to achieve stable electronic configuration with full electron
shells - form ions with 1- charge
- react with metals to form ionic compounds
as we move down Groupon VII reactivity of halogen___
reactivity decreases and become weaker oxidising agents
- the atoms become larger
- the valance electrons are further away from the nucleus
- weaker electrostatic forces of attraction between the nucleus and the valance electrons
- this makes it difficult for the nucleus to attract an additional electron into the valance shell
the more reactive halogen is able to displace the less reactive halogen in a solutions
format eg. chlorine, being more reactive that bromine, gains electrons more readily, hence it is able to displace bromine from sodium bromide
noble gases
exists as monoatomic gases
physical properties of noble gases
- very low melting and boiling points
- colourless gases
as we move down the group 0
- bp increases
- density increases
chemical properties of group 0
- unreactive as the valance shell is completely filled and have achieved stable electronic configuration with full electronic shells
