Atomic Structure and the Periodic Table Flashcards
What are the smallest parts of an element that can exist?
Atoms
How big are atoms?
Radius of 0.1nm
1x10^-10m
What are atoms made up of?
Protons
Neutrons
Electrons
What makes up the nucleus?
Protons
Neutrons
Where are electrons found?
Outside the nucleus in energy levels (shells)
What is the relative charge of a proton?
+1
What is the relative charge of a neutron?
0
What is the relative charge of an electron?
-1
What is the relative mass of a proton?
1
What is the relative mass of a neutron?
1
What is the relative mass of an electron?
Very small
1/2000
How big is the nucleus in comparison to the atom?
10 000 times smaller
What charge are atoms?
Neutral
What does the mass number show us?
Protons + neutrons
What does the atomic number show us?
Number of protons
What are isotopes?
Are atoms of the same element that have a different mass number. Same number of protons but different number of neutrons
What is the relative atomic mass of an element?
Average mass of all isotopes of an element.
Total mass of all the atoms of an element
___________________________________________
Total number of atoms of an element
How many electrons can the 1st energy level hold?
2
How many electrons can the 2nd energy shell hold?
8
How many electrons can the 3rd energy level hold?
8
What are ions?
Particles with an electric charge because they contain a different number of protons and electrons
Which ion has more protons than electrons?
Positive
What kind of ion has more electrons than protons?
Negative
What was the plum pudding model?
In this model, the atom is a ball of positive charge with negative electrons embedded into it
What did the alpha particle scattering experiment disprove?
The plum pudding model
What happened in the alpha particle scattering experiment?
Alpha particles were fired at a very thin price of gold foil. If the plum pudding model was correct, the alpha particles would have passed straight through . However a few alpha particles were deflected or bounced back.
What did Rutherford work out from the results from the alpha particle scattering experiment
Atoms have a tiny, positive nucleus surrounded by electrons. Most of the mass of an atom is concentrated in this nucleus. This is known as the nuclear model.
What did Bohr discover?
That electrons were contained in energy levels
What did Chadwick work out?
The nucleus contains both protons and neutrons.
What is an element?
A substance contains one type of atom
Can element be broken down into simpler substances
No
How many element are there?
Just over 100
What is the order used for the periodic table?
Atomic number
Roughly how many of the elements are metals?
3/4
How are compounds formed?
When elements react with each other
What occurs when elements react?
Electrons are transferred or shared so that atoms obtain stable electron structure
What kind of compound is formed when a a metal and non metal react?
Ionic
What type of compound is formed when a metal reacts with a metal?
None because they do not react
What type if compound is formed when a non metal reacts with a non metal?
Molecular
What are reactants?
The chemicals at the start of a reaction
What are products?
The chemicals made in a reaction
What do elements in the same group have in common?
Same number of electrons in outer shell
Similar chemical properties
What is the name of group 0?
The noble gases
Name 3 noble gases?
Helium
Neon
Argon
Are the noble gases non metal or metal?
Non metals
Why are noble gases very unreactive?
Stable electron structures
What colour are noble gases at room temperature?
Colourless
Why do noble gases have a very low boiling point?
Atoms are not bonded together and there are only weak forces between atoms
What happens when you go down group 0?
The boiling points increase because the atoms get heavier and the forces between atoms increase
What is the name of the elements in group 1?
Alkali metals
Name three alkali metals
Lithium
Sodium
Potassium
Name the properties of an alkali metal
Soft metal with low density and a low melting point
What are alkali metals very reactive?
One electron in outer shell which is easily given away
What do alkali metals form when they react?
1+ ions in an ionic compound
What happens when lithium reacts with oxygen?
Burns with crimson flame to form white powder
What happens in the reaction between sodium and oxygen?
Burns with yellow flame to form white powder
What happens when potassium reacts with oxygen?
Burns with lilac flame to form white powder
What happens when lithium reacts with chlorine?
Burns with crimson flame to form white powder
What happens when sodium reacts with chlorine?
Burns with yellow flame to form white powder
What happens when potassium reacts with chlorine?
Burns with lilac flame to form white powder
What happens when lithium reacts with water?
Moves around on surface of water and fizzes
What happens when sodium reacts with water?
Melts, moves around on the surface, fizzes and catches fire with yellow flame
What happens when potassium reacts with water?
Melts, moves around on the surface of the water , fizzes and then catches fire with lilac flame
What is formed when an alkali metal reacts with water?
Solution of metal hydroxide and hydrogen gas is formed. Metal hydroxides are alkalines.
Describe the trend in reactivity in the alkali metals.
More reactive going down the group
Because
The outer electron is further from nucleus
Attraction between outer electron and nucleus is weaker
The outer shell Is lost more easily
What are the transition metals?
Block of elements between groups 2 and 3
Name some common transition metals
Iron
Gold
Silver
Copper
Name some properties of the transition metals
High melting point Not very reactive Compounds are coloured High density Strong and hard Form different ions Useful as catalyst Form ionic compounds reaction with non metals Good thermal and electrical conductors
What are the elements called in group 7?
The halogens
Name some halogens
Fluorine
Chlorine
Bromine
Iodine
Are the halogens metals or non metals?
All non metals
What is each halogen made of?
Diatomic molecules
Why do the halogens have low melting points
Weak forces between the molecules
What happens as you go down the group?
Melting points increase because forces between molecules get stronger
What is fluorine colour?
Yellow gas
What is chlorines colour as a gas?
Green gas
What is bromines colour as a liquid?
Orange brown liquid
What is iodines appearances as a solid?
Grey solid
How many electrons in the outer shell do the halogens have?
7
How do they gain 1 electron when they react?
Forming 1- ions when they react with metals
Forming covalent bonds by sharing electrons when they react with non metals
What happens when sodium bromide reacts with chlorine water?
Yellow solution forms as chlorine displaces bromine . Chlorine is more reactive
What happens when sodium iodide reacts with chlorine?
Brown solution forms as chlorine displaces iodine. Chlorine more reactive
What happens when sodium iodide reacts with bromine water?
Brown solution forms as bromine displaces iodine. Bromine more reactive
Describe the trend in reactivity of the halogens
Less reactive going down the group Because Harder to gain electron Electron gained further from nucleus Attraction between electron Gaines and nucleus is weaker
What will a more reactive halogen do to a less reactive halogen when reacted?
More reactive displaces a less reactive halogen from its compounds
What is a mixture?
Two or more substances that are mixed together and not chemically combined
What is a compound?
Substance made from two or more elements chemically bonded together
What are the proportions of a mixture?
Can be mixed in any proportion
What are the proportions of a compound?
Elements combined in a fixed proportion
Are mixtures easy to separate?
Yes by physical methods because they are not chemically bonded together
Why can’t compounds be separated by physical methods?
They are chemically bonded together
Describe filtration
Separates insoluble solid and liquid
Liquid goes through filter paper, solid doesn’t
E.g. Sand and water
Describe evaporation/ crystallisation
Separates soluble solid from a solution
Evaporation: solvent evaporates leaving the solid
Crystallisation: some of the solvent evaporated and then crystals of the solid formats he solution cools
E.g. Salt from a solution of salt water
Describe chromatography
Separates mixture is soluble solids
Substances dissolve in the solvent and move up the paper at different speeds
E.g. Mixture of dyes
Describe simple distillation
Separates solvent from a solution
The solvent boils off leaving the solid behind. The vaporised solvent cools and is condensed back into a liquid
E.g. Water from a solution of sea water
Describe fractional distillation
Separates miscible liquids
The liquids have different boiling points and so boil off separately
E.g. Ethanol from a mixture of water and ethanol
Describe separating funnel
Immiscible liquids
The liquids form two layers as they do not mix together
E.g. Oil from a mixture of oil and water
What is the modern periodic table based on?
Mendeleev table
What did Mendeleev do?
Put most of the element in mass order but changed it around to fit the properties
Predicted the existence of new elements he left gaps for
