1. Atomic Structure & The Periodic Table Flashcards
How do you work out the mass number?
number of neutrons + number of protons
What happens when you get more electrons?
You get more shells
How do you work out the atomic number?
Number of protons = number of electrons
How do you work out the number of neutrons?
Mass number - Atomic Number
What are isotopes?
Atoms of the same element with a different number of neutrons
What is the radius of an atom?
1x10m to the -10
What is the electronic configuration?
1st shell - 2 electrons
2nd shell - 8 electrons
3rd shell - 8 electrons
4th shell - 8 electrons
What do number of shells equal?
Period number
What do number of outer electrons equal?
Group number
Why are noble gases unreactive?
Because they have a full outer shell
Can noble gases form compounds?
No
What is a compound?
1 or more different types of atom that are chemically bonded
What is an atom?
The smallest part of any substance
What is an element?
Contains one type of atom
What is a molecule?
Contains 2 or more atoms joined together that are either the same or different
What is a mixture?
A material that contains one or more than one type of substance
What is an ionic compound?
contains metal and non-metal atoms
What is a covalent compound?
Contains only non metals
What are examples of sub-atomic particles?
Proton Neutron Electron Nucleus Shell (energy level)
What was the plum pudding theory?
The atom was imagined as a sphere of positive charge with negatively charged electrons dotted around in side
What state are noble gases as room temperature?
Colourless gases
What is the pattern of boiling point in noble gases?
The boiling point increases down the group
What does fizz show when an alkaline metal has reacted?
A gas has been given off
Equation for when an alkaline metal reacts with oxygen?
metal + oxygen -> metal oxide
Equation for when an alkaline metal reacts with water?
metal + water -> metal hydroxide + hydrogen
What happens to the density in group 1 metals?
It increases down the group
What happens to melting and boiling point in group 1 metals?
It decreases down the group
What happens to the density of transition metals down the group?
They are consistently high and they increase down the group
What is the trend in melting and boiling point down group 7?
Down the group the boiling and melting points increase
What happens to the reactivity down group 7?
It decreases
What type of mixture is separated when decanting?
- insoluble solid from a liquid
* liquid from an unsoluble solid
What type of mixture is separated in filtration?
- liquid from an insoluble solid
* insoluble liquid from solid
What type of mixture is separated in evaporation?
• solute from a solution
What type of mixture is separated in distillation?
• solvent from a solution
What type of mixture is separated in fractional distillation?
Mixture of miscible liquids
What type of mixture is separated with a separating funnel?
Mixture of immiscible liquids
What type of mixture is separated in chromatography?
Mixture of soluble solids
Example of the solvent?
Water
Example of the solute?
Salt
Example of products after decanting?
Water from sand
Example of products after filtration?
Water from sand
Example of products after evaporation?
Salt from salt solution
Example of products after distillation?
Water from salt solution
Ethanol and water
Alcohol from sugar dissolved in alcohol
Example of products after fractional distillation?
Petrol and diesel from crude oil
Ethanol and water
Example of products after using a separating funnel?
Oil and water
Example of products after chromatography?
Mixture of food dyes
Properties of transition metals?
Have ions with different charges, useful as catalysts, form coloured compounds, not very reactive, high melting points, strong and hard
How are elements in the periodic table arranged today?
Atomic number
Before discovery of sub atomic particles, how was the periodic table arranged?
Atomic mass
What were the early problems with the periodic table?
Not many elements discovered, atomic weights were inaccurate, no gaps left for unknowns, not every element followed the pattern
How did Mendeleev overcome each problem with his periodic table?
Followed the pattern, left spaces for new elements (and predicted unknowns)
What happened for scientists to believe Mendeleev’s theory?
Discovered a new element that fitted his prediction