Atomic structure and periodic table

Created by

Lorelie

Cards (55)

What is an isotope?
Atoms of the same element that have different numbers of neutrons
What is a compound? 
two or more elements chemically bonded together
What does paper chromatography do ?
Separates substances in a mixture
What is a mixture?
A combination of two or more substances that have no chemical bond
What does filtration separate?
Insoluble solids from liquids
What does distillation separate?
A soluble slid and a liquid
Who described atoms as solid spheres?
John Dalton
What did the different spheres represent
Different elements
Who discovered electrons 
JJ Thomson
What was his mode of the atom called
Plum pudding model
Describe the plum pudding model
the atom is a ball of positive charge with negative electrons embedded in it
Who showed the plum pudding model was wrong
Rutherford
What experiment did Rutherford do?
Alpha particle scattering
What happened in this experiment
They fired alpha particles at an extremely thin sheet of gold
What did they expect to happen
The particles were expected to pass straight thorough or be slightly deflected at most
Why did they expect this
The positive charge of each atom was thought to be very spread out
Wha actually happened 
Most particles passes straight through
Some were deflected more than expected
A small number were deflected backwards
Why did they pass through
Most of the atom is empty space
Why were some deflected
Alpha particles came near the concentrated positively charged nucleus
Why were some deflected backwards
They were fired directly a the nucleus
What model of the atom did Rutherford come up with
Nuclear model
Describe the nuclear model
Tiny positively charged nucleus at the centre
A cloud of negative electrons surrounded the nucleus
What did Bohr discover?
Electron shells
Who discovered protons 
James Chadwick
Describe the periodic table in the early 1800s
Electrons were arranged by atomic mass
Some elements were laced in the wrong group
How did Mendeleev organize his periodic table?
Mainly in order of atomic mass
Grouped elements with similar properties
Left gaps for undiscovered elements
How is the modern periodic table arranged
Increasing proton number
Elements with similar properties are in groups
What is a metal 
Elements that can form positive ions when the react
What's a non metal
An element that doesn't generally form positive ions when it rects
Properties of meals 
Strong
Malleable
Good conductors (heat and electricity)
High boiling and melting points
Properties of non metals
Dull
Brittle
Poor conductors
Lower density
What are the different properties of a transition metal 
Can have more than one ion
Their ions are often coloured
Transition metal compounds often make good catalysts
What are group 1 metals called
Alkali metals
What are their properties 
Soft and have low density
What are the trends as you go down the group(group 1) 
INCREASING reactivity
LOWER melting and boiling points
HIGHER relative atomic mass
Reaction with water 
They read vigorously to produce HYDROGEN GAS and METAL HYDROXIDES
Amount of energy released by the reaction INCREASES down the group
Reaction with chlorine 
When heated in chlorine gas they form WHITE METAL CHLORIDE SALTS
Reaction with oxygen 
Form a metal oxide
Why do they tarnish in the air
Metal reacts with oxygen to form a dull metal oxide layer
Why are they called alkali metals
The hydroxides the produce in water dissolve to produce alkaline solutions