C1&2 (Atoms, Elements And Compounds) Flashcards
(30 cards)
What is an element
- simple substance
- cannot be split up smaller through chemical reactions
- particles that make up an element are called atoms (same kind)
What is an atom
- smallest part of an element which can exist
- protons, neutrons and electrons are subatomic particles
Where are protons, neutrons and electrons found?
Protons and neutrons- nucleus
Electrons- outer shell/ energy level
Protons, neutrons and electrons relative charge and mass
Protons- RC +1 RM 1
Neutrons- RC 0 RM 1
Electrons- RC -1 RM 1/2000
Radius of an atom and the nucleus
Atom- 0.1 nm
Nucleus- 1/10,000
Molecules
A group of atoms covalently bonded
Noble gasses= monatomic elements
- consisting of a single atom (goes around on its own)
Diatomic elements
- consisting of two atoms covalently bonded
Polyatomic elements
- consisting of multiple atoms covalently bonded
What is a mixture?
- two or more elements or compounds not chemically bonded
- chemical properties are unchanged in each mixture
What are isotypes?
Atoms of the same element that have a different number of neutrons
What is the Plum Pudding model?
- J J Thompson
- atom is a ball of positive and negative charge
What is the nuclear model?
- dense positive centre
- with negative charge randomly around it
Niels Bohr work?
Adapted the nuclear model to suggest the electrons orbit the centre
What is an ion?
- charged atom or group of atoms
- gaining or loosing an electron
Periodic table: 1808 John Dalton
- ordered elements through the atomic weight
Periodic table: John Newlands 1864
- ordered the elements in order of mass
- didn’t leave space for predicted elemente
Periodic table: 1869 Dimitri Mendeleev
- periodic table know today
- atomic mass and columns for similar properties
- left space for predicted elements
Properties of metals
- malleable
- good conductors of electricity
- high melting point
- sonorous (ring when hit)
- solid at room temperature
Properties of Non-Metals
- non malleable (brittle)
- not good conductors
- negative ions
- low melting point
- gas or liquid state
Reaction in Group 1 elements
Alkali Metals
- extremely reactive
- donate their outer most electron (positive ion)
- more outer most shell, electrostatic attraction weakens
- react with oxygen to form a base
- react with water to produce alkali or hydrogen gas
Physical properties of halogens
- low melting point, increases going down
- poor conductors of electricity
- as it goes down you gain an electron, less energy levels means it is easier to grab an electron
- minus 1 charge
Displacement theory
If the metal halide is mixed with the more reactive hydrogen, the extra electron will transfer from less reactive to more reactive.
Properties of transition metals
- good conductors
- less reactive then group 1
- high density
- can be used as catalysts
- high melting point
- reacts slowly with air and water
- malleable and ductile
- lustrous
- harder then group 1
- they make coloured compounds
- have different ion charges
