Atomic Structure and the Periodic Table Flashcards
Define a mixture.
two or more elements or compounds not
chemically combined together.
In what physical processes can a mixture be separated?
filtration,
crystallisation, simple distillation, fractional distillation and
chromatography.
What is chromatography used for?
Separation of coloured compounds.
What were atoms thought to be before the discovery of the electron?
Tiny spheres that could not be divided.
What model of the atom followed the discovery of the electron?
The Plum Pudding Model.
Describe The Plum Pudding Model.
The atom is a ball of
positive charge with negative electrons embedded within it.
What did Ernest Rutherford do to discover the nuclear model?
Fire alpha particles at a peace of gold leaf and observed scatter. Thusly proved that the mass of an atom was concentrated at the centre and that this was positively charged.
What was the Nuclear Model?
A model which suggested most of the mass of an atom was at a very small point (nucleus) which was positively charged orbited by electrons.
How did Niels Bohr adapt the nuclear model?
Suggested that electrons orbit at different distances.
How was the Nuclear model adapted to explain the nucleus?
The nucleus’ charge meant that it could be subdivided to a number of smaller positively charged particles. This was the introduction of the Proton.
How did James Chadwick contribute to the nuclear model?
Showed the existence of neutrons within the nucleus.
What are the relative electrical charges of particles in the atom?
Proton +1, Neutron 0, Electron -1.
In an element, the number of electrons is equal to?
The number of Protons.
What are the relative mases of particles in the atom?
Proton 1, Neutron 1, Electron ~0.
What is the atomic mass?
The sum of the protons and neutrons in an atom.
What are isotopes?
Atoms of the same element with different numbers of neutrons.
What is the atomic number?
The number of protons in the nucleus.
What is the relative atomic mass of an element?
The average mass of an element in accordance to the abundance of different isotopes.
How do electrons occupy an atom?
The innermost available shell/ lowest available energy level.
How elements arranged in the periodic table?
In order of atomic
(proton) number.
Columns of the periodic table are known as?
Groups.
Rows of the periodic table are known as?
Periods.
What do elements in the same group have in common?
The number of electrons in their outermost shells and similar properties?
What were some of the problems with early periodic tables?
Arranged in order of atomic mass.
that people were working from an incomplete set of data.
Who came up with an appropriate early version of the periodic table?
Mendeleev
How was Mendeleev’s periodic table different?
Gaps were left for undiscovered elements,
some elements were reordered.
What could Mendeleev do with his version of the periodic table?
Predict properties of undiscovered element.
What caused irregular ordering by atomic mass.
Isotopes could cause certain elements to be heavier- Mendeleev used this to explain his reordering.
What are metals?
Elements that form positive ions.
What are non-metals?
Elements that form negative ions.
What are group 0 elements called?
Noble gases
What are the properties of Group 0 elements?
Unreactive,
stable,
8 electrons in outer shell (2 for Helium),
boiling points increase with increasing relative mass.
What are Group 1 elements called?
Alkali metals
What are the properties of Group 1 elements?
Reactive,
1 electron in outer shell,
reactivity increases as relative mass increases.
What are Group 7 elements called?
Halogens
What are the properties of Group 7 elements?
Exists as paired molecules,
7 electrons in outer shell,
reactivity increases as relative mass increases,
involved in displacement reactions.
What are some properties of transition metals?
have ions with different charges,
form coloured compounds,
are useful as catalysts.
