Atomic Structure And The Periodic Table Flashcards
(41 cards)
What was Rutherford’s nuclear model of the atom?
There is a tiny, positively charged nucleus at the centre, where most of the mass is concentrated. A ‘cloud’ of negative electrons surrounds the nucleus - so most of the atom is empty space. When alpha particles came near the concentrated, positively charge of the nucleus, they were deflected. If they were fired directly at the nucleus, they were deflected backwards. Otherwise, they passed through the empty space.
Ways to separate mixtures
- Filtration
- crystallisation
- simple distillation
- fractional distillation
- chromatography
How big is an Atom’s radius?
0.1 Nanometers (1x10^-10m)
What did James Chadwick find?
He provided evidence for neutral particles in the nucleus which are now called neutrons.
What did Mendeleev do in 1869?
He took 50 known elements and arranged them into his own table of elements. He put them mainly in order of atomic mass but did switch that order if the properties should be changed.
What is an ion?
And ion is an atom or a group of atoms that have lost or gained electrons
What do atoms contain?
Protons, Neutrons and Electrons
Metals
- have metallic bonding
- they’re strong
- can be bent into different shapes
- can conduct heat and electricity
- high boiling and melting points
Group 1
- alkali metals
- soft
- low density
- react with water
- produce hydrogen
- form hydroxides that dissolve in water
What decides what type of atom it is?
The number of protons in the nucleus
What did Rutherford find?
He found that most of the particles did go straight through the gold sheet and some were deflected more than expected, and small number where deflected backwards.
Atoms have…?
The same number of protons and electrons
What did Bohr’s nuclear model suggest?
All the electrons where contained in shells
Group 7
- Halogens
- less reactive as you go down
- highs melting and boiling points as you go down
- have higher relative atomic masses as you go down
Atoms are…?
Neutral (no charge)
What does the mass number tell us?
The number of protons and neutrons there are in an atom
What are isotopes?
Isotopes are different forms of the same element that has the same number of protons but different number of neutrons (same Atomic number and different Mass number)
What did JJ Thomson conclude in 1897?
Atoms weren’t solid spheres. His measurements of charge and mass showed an atom must contain even smaller, negatively charged particles - electrons. He ‘solid sphere’ idea of atomic structure had to be changed. The new theory was known as the ‘plum pudding model’
What does 2- mean?
2 more electrons than protons
What is ionic bonding?
The opposite charges of the ion means they are strongly attracted to each other
Non-metals
- don’t have metallic bonding
- dull looking
- aren’t always solids at room temperature
- don’t conduct electricity
- lower density
What did John dalton describe atoms as in the 19th century?
Solid spheres. He said that different spheres made up different elements
Group Number
It tells us how many electrons are in its outer shell. E.g group seven all have 7 electrons in their outer shell.
What is the plum pudding model?
It showed the atom as a ball of positive charge with electrons stuck on it.
