C4
- Created by: emchown
- Created on: 10-03-15 16:04
View mindmap
- C4
- Atoms
- All substances are made up of atoms.
- Each atom has: A central nucleus (made up of protons and neutrons); electrons arranged in shells .
- Atoms have the same number of protons and electrons (neutral)
- Proton has the same mass as neutron
- A substance that only has one type of atom is an Element
- Elements in periodic tbale arranged in order of increasing atomic number
- Electronic Configuration
- Electrons in an atom occupy the lowest avalible shells
- The first shell can only hold up to 2 electrons
- The rest of the shells hold up to 8 electrons
- Electronic Configuration
- Electrons in an atom occupy the lowest avalible shells
- The first shell can only hold up to 2 electrons
- The rest of the shells hold up to 8 electrons
- The rest of the shells hold up to 8 electrons
- The amount of electrons in an outer shell determines what group of the periodic table its in
- The chemical properties of an element are determined by its electron arrangment
- Electronic Configuration
- The rest of the shells hold up to 8 electrons
- The amount of electrons in an outer shell determines what group of the periodic table its in
- The chemical properties of an element are determined by its electron arrangment
- Spectroscopy
- Light emitted from flame of element produces characteristic line spectrum
- Each line in spectrum represents an energy change
- Electrons falls from high energy levels to low.
- Lithium - Red flame
- Sodium - Yellow flame
- Potassium - Lilac flame
- Developing the periodic table
- John Newlands (1864)
- Only knew existence of 63 elements
- Arranged elements in order of atomic mass
- Found similar properties amongst every 8th element
- Society ridiculed his idea
- Dobereiner (1829)
- Arranged elements into groups of 3 (triads)
- Elements in a triad had similar chem. properties
- R.A.M of middle one was halfway between other 2
- Atomic mass was measured relative to hydrgens mas
- John Newlands (1864)
- Safety Precautions
- Gloves
- Eye protection
- Wash hands after
- Safety screens
- Small amounts and low concentrations of chemicals
- Work in fume cupboard/ventilating room
- Not eating or drinking when working with chemicals
- Not working near naked flames
- Group 1 - The Alkali Metals
- Metals become more reactive down the group
- Low melting points
- Melting and boiling points decrease down group
- Alkali Metal Compounds
- When the metals they react they form compounds that are similar
- Reactions become more vigorous down group
- Reactions with Chlorine
- Reacts vigorously
- Form colourless crystalline salts (metal chlorides)
- Lithium + Chlorine = Lithium Chloride
- Reaction with Water
- Li, Na and K float on cold water (low density)
- Heat from reaction turns Na and K into liquids
- Fizz
- Hydrogen gas formed
- Down group, reaction more violent
- Metal Hydroxide and Hydrogen gas formed
- Alkali solution formed
- Potassium + Water = Potassium Hydroxide + Hydrogen
- Trends
- Have similatr properties because same number of electrons in their outer shells
- More reactive down the group because outer electron shell further away from influence of nucleys so an electron is lost more easily
- Group 7 - The Halogens
- Less reactive down the group
- Higher melting and boiling points down group
- All holagen consist of Diatomic pairs (pairs of atoms)
- Chlorine
- Green gas
- Used to sterilise water
- Make pesticides and plastics
- Bromine
- Orange liquid
- Brown gas when heated
- Iodine
- Purple/dark grey solid
- Pale purple gas when heated
- Used as an antiseptic
- Densities increase down group
- Displacement Reactions
- A more reactive halogen will displace a less reactive one from an aqueous solution of its salt
- e.g. chlorine will displace bromine and iodine
- Displacement Reactions
- A more reactive halogen will displace a less reactive one from an aqueous solution of its salt
- e.g. chlorine will displace bromine and iodine
- e.g. chlorine will displace bromine and iodine
- potassium iodide + chlorine = potassium chloride + iodine
- A more reactive halogen will displace a less reactive one from an aqueous solution of its salt
- Displacement Reactions
- e.g. chlorine will displace bromine and iodine
- potassium iodide + chlorine = potassium chloride + iodine
- A more reactive halogen will displace a less reactive one from an aqueous solution of its salt
- Compounds
- When they react, they form compounds that are similar
- The reactivity decreases down the group
- Halogens react with alkali metals and ions
- Reaction between chlorine and iron is more vigorous than between iodine and iron.
- Trends
- They have similar properties because they have the same number of electrons in their outer shell
- They are less reactive down the group because the outer electron shell is firther away from influence of the nucleus so an electron is gained less easily.
- Properties of Compounds
- Chemists use their observations to develop theories to explain the properties of different compounds
- e.g. molten compounds of metals with non-metals (lithium chloride) conduct electricity
- There are charged particles in molten compounds known as Ions
- Ions
- If an atom loses or gains one or more electrons it carries an overall charge because protons and electrons no longer equal
- When this happens, atom becomes an ion
- If an atom loses or gains one or more electrons it carries an overall charge because protons and electrons no longer equal
- If an atom loses an electron, the ions has a positive charge
- If an atom gains an electeron, the ion has a negative charge
- The Ionic Bond
- An ionic bond occures between a metal and a non-metal
- Involves the transfer of electrons between two atoms to from electrically charged ions
- Each ion has a full outer shell
- Compounds of Group 1 and 7 elements are ionic compounds
- Sodium and Chlorine (Sodium Chloride)
- Bond ionically
- Sodium loses one electron (positive charge) and Chlorine gains the electron (negative charge)
- Positive and negative ions are then electrostatically attracted to eachother .
- Froms a giant crystal lattice
- Sodium and Oxygen (Sodium Oxide)
- Oxygen wants two electrons and gains them from two sodium atoms
- Magnesium and Oxygen (Magnesium Oxide)
- Mg loses two electrons and Oxygen gains two
- Forms crystals because ions arranged into a regular lattice
- Ions have strong forces of attraction between them whcih takes a lot of energy to break
- Ionic compounds have hugh melting and boiling points
- When compound molten or dissolved, forces weakened and ions free to move - conduct electricity
- Atoms
Comments
No comments have yet been made