Atomic Structure And The Periodic Table Flashcards
What are all substances made of?
Atoms
How are compounds formed
Formed from elements by chemical reactions
What can only be separated into elements by chemical reactions.
Compounds
Mixture consists of what?
two or more elements or compounds not chemically combined together.
Mixtures can be separated by?
filtration, crystallisation, simple distillation, fractional distillation and chromatography. These physical processes do not involve chemical reactions and no new substances are made.
Before the discovery of electrons what were atoms described as
atoms were thought to be tiny spheres that could not be divided.
What did the plum pudding model suggest?
The plum pudding model suggested that the atom is a ball of positive charge with negative electrons embedded in it.
What led to the plum pudding model
Thé électron
What did The results from the alpha particle scattering experiment lead to?
conclusion that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was charged
Niels Bohr?
adapted the nuclear model by suggesting that electrons orbit the nucleus at specific distances.
What was the name given to the particles that the positive charge of any nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge.
Proton
James Chadwicks experiment?
provided the evidence to show the existence of neutrons within the nucleus.
why the new evidence from the scattering experiment led to a change in the atomic model?
led to the conclusion that the mass of an atom was concentrated at the centre (nucleus) and that the nucleus was charged
In an atom, the number of electrons is equal to the number of…
Protons in the nucleus
The sum of the protons and neutrons in an atom is
It’s mass number
Atoms of the same element can have different numbers of neutrons, what is this called?
these atoms are called isotopes of that element.
Mass number?
The top number
The atomic number
The bottom number
What occupies the lowest available energy levels
The electrons in an atom
How many electrons fit in the first line of an atom
2
How many electrons fit on the second line of an atom
8
The elements in the periodic table are arranged in order of
atomic (proton) number and so that elements with similar properties are in columns, known as groups
The table is called a periodic table because
because similar properties occur at regular intervals.
Elements in the same group in the periodic table have the same number of
Electrons in their outer shell
Before the discovery of protons neutrons and electrons elements were arranged in
Order of their atomic weight
Mendeleev overcame some of the problems in the periodic table by
leaving gaps for elements that he thought had not been discovered and in some places changed the order based on atomic weights.
Knowledge of isotopes made it possible to explain what?
the order based on atomic weights was not always correct.
Elements that react to form positive ions?
Are metals
Elements that do not form positive ions?
Are non-metals
Where are metals found on the periodic table?
To the left, and bottom
Where are non-metals found on the periodic table?
To the right and top
What are the elements in group 0 called?
Noble gases
Why are noble gases unreactive?
because their atoms have stable arrangements of electrons.
The boiling points of the noble gases increase with
Increasing relative atomic mass
The elements in Group 1 of the periodic table are known as?
The alkali metals
Explain why alkali metals have characteristic properties ?
Because because of the single electron in their outer shell
The elements in Group 7 of the periodic table are known as?
The halogens
Define Halogens
Non metals and consist of molecules made of pairs of atoms.
In Group 7, the reactivity of the elements increases or decreases?
decreases going down the group.
A more reactive halogen can…
displace a less reactive halogen from an aqueous solution of its salt.
Who made the first atom model? And what was it called?
Dalton made the first atom and it was called a solid atom
What was the second atom model? Who made it? What did it look like?
Plum pudding model created by JJ Thornton.
Positively charged sphère with negative electrons dotted around
Who made the third atom model? What was it like? What was it called?
Nucleur model
Rutherford
Dense positively, charged nucleus sur landed by a cloud of electrons
What was the 4th atom called? Who made it? What was it like?
Bohr
The atom
Electrons are in shells specific distances from the nucleus
What was the add on from the 4th model? Who created it? What was it like?
Chadwick
Positive and negatives created the nucleus
Discovered the neutron
And created isotopes
Molecule?
Two or more atoms chemically bonded together
Compound?
Substances made from two or more elements chemically bonded together
What is filtration?
Using a filter to separate an insoluble solid from a liquid
