Atomic Structure and The Periodic Table Flashcards
What is an Element
A substance that contains only one type of atom
What is a compound
A substance that contains atoms of two or more elements which are chemically combined
What is a Mixture
two or more elements or compounds which are not chemically combined
What is filtration used for
to separate soluble solids from insoluble solids
What is Crystallisation used for
to obtain a soluble solid from a solution
What and how is simple distillation used
Used to obtain a solvent from a solution
- Boil a set volume of water so that it changes into gas
- Water collects into the condenser and changes from a gas to liquid collected in a baker
What is fractional Distillation used for
to separate mixtures in which they components have different boiling points
What is the Atomic Number
The number or protons
What is the mass number
No. protons + No. neutrons
What is an isotope
Atoms of an element with the same number of protons but a different number of neutrons
What ions do metals form
They loose electrons to form positive ions
Why is a negative ion formed when an electron is gained
Gaining an electron means the overall charge will be -1 (negative) as there is one less positive proton - vice versa
What ions do non-metals from
they gain electrons to form a negative ion
What were the problems with John Newlands model of the periodic table and how did Mendeleev fix it
-after subatomic particles were discovered
- Newlands model strictly followed atomic weight which meant some of the elements were in the wrong place
- Mendeleev realised some elements were yet to be discovered so left gaps and reordered some elements
- Placed in groups with similar properties
- When subatomic particles were discovered it revealed he had organised them in increasing atomic number
What are the group 0 elements named as and what makes them unreactive
Noble gases
- have a full outer shell so very table electron configuration
- boiling points increase down the group
What are the properties of group 1 metals and what happens when they react with water
- the have low melting and boiling points
- alkali metals
- potassium + water —> potassium hydroxide + hydrogen
- produces a alkaline solution
- low densities (lithium, sodium and potassium float on water as they are less dense than it)
Why do Group 1 metals become more reactive down the group
The electron gets further away from the influence of the nucleus so can be lost more easily
What happens when group 1 alkali metals react with non-metals
They form ionic compounds where the metal atom looses one electron to from a metal ion with a positive charge
Why does reactivity decrease down the group 7
The outer shell becomes further away from the influence of the nucleus and is shielded by more electrons making it harder to gain an electron.
What happens when group 7 halogens react with metals
What happens when a more reactive halogen reacts with a less reactive one
They form ionic salts - the halogen atom gains one electron to form a halide ion with a negative charge
A more reactive halogen displaces a less reactive one to form an aqueous solution of its salts
What happens when a more reactive halogen reacts with a less reactive one
It will displace it to from an aqueous solution of its salts
- Chlorine will displace bromine from potassium bromide
What charges do transition metals have and what can the be used for
They have ions with different charges
Can be used as catalysts and are good conductors of heat and electricity
