1 - Atomic structure Flashcards
(27 cards)
What does aqueous mean?
dissolved in water
what is an element?
a pure substance consisting of only atoms that have the same number of protons in their atomic nuclei
What are the elements in group 0 called?
Noble gases
What are the properties of noble gases?
Unreactive
Full outer shell of electrons
Exist as single atoms
Boiling points increase as you go down the group
What are the elements between groups 2 and 3 called?
transition metals
What are the properties of transition metals?
High melting points
High densities
Great strength/hardness
Shiny when freshly cut
Electrical conductors in solid and liquid form
What are the elements in group 7 called?
Halogens
What does halogen mean?
Salt former (when halogens react with metals they form salts)
What do all halogens require?
An extra electron that they share with another atom (they are diatomic molecules)
What are the properties of halogens?
Boiling points increase as you go down the group
Form negative ions with a single negative charge
Diatomic molecules
What are the elements in group 1 called?
Alkali metals
What are the properties of alkali metals?
Very reactive
Soft
Form alkali solutions when they react with water
1 electron in their outer shell
More reactive/lower melting and boiling point as you go down the group
Who came up with the idea that all matter is made up from tiny particles called atoms?
Democritus
What did John Dalton discover?
Elements couldn’t be broken into anything smaller
Atoms have different atomic weights
Who grouped elements with similar properties?
Johann Wolfgang Döbereiner
What did John Newlands notice?
Patterns when listing elements according to increasing atomic weight, but couldn’t always get the patterns to work
What did Dmitri Mendeleev do?
Studied all the known elements and arranged them to make sense
He left gaps in the table but worked out that they were for undiscovered elements
What is a compound?
Two or more different atoms that are chemically bonded together
What is a mixture?
Two or more different things mixed, but not chemically bonded, together
What are the relative charges/masses of protons, electrons and neutrons?
Protons:
Relative charge = +1
Relative mass = 1
Neutrons:
Relative charge = 0
Relative mass = 1
Electrons:
Relative charge = -1
Relative mass = very small
What is a molecule?
Two or more of the same atom bonded together
How many electrons can go in the first shell of an atom?
2
Who discovered electrons and in what year?
J J Thompson
1897
Plum pudding model (atoms were positive balls with negative electrons inside of them)
Who discovered the nucleus and in what year?
Ernest Rutherford
1911
Nuclear model (nucleus at centre surrounded by electrons)
