Atomic structure + Periodic Table Flashcards
Give the meaning of ‘isotopes’. (2)
(atoms with the) same number of protons
(but with) different numbers of neutrons
Which statement about the elements in Group 0 is correct?
Tick (✓) one box.
All elements in the group are very
reactive.
All elements in the group form negative ions.
The boiling points increase down the
group.
The relative atomic masses (Ar)
decrease down the group.
the boiling points increase down the group
What is the most likely formula of a gallium ion?
Ga3+
Gallium was discovered six years after Mendeleev published his periodic
table.
Give two reasons why the discovery of gallium helped Mendeleev’s
periodic table to become accepted.
(gallium) fitted in a gap (Mendeleev had left)
(gallium’s) properties were predicted correctly (by Mendeleev)
The plum pudding model did not have a nucleus.
Describe three other differences between the nuclear model of the atom
and the plum pudding model.
nuclear- mostly empty space
allow the plum pudding model has no empty space
the plum pudding model is solid
the positive charge is (all) in the nucleus
allow in the plum pudding model the
atom is a ball of positive charge (with
embedded electrons)
the mass is concentrated in the nucleus
the electrons and the nucleus are separate
allow in the plum pudding model the
electrons are embedded
Describe the change that Bohr made to the nuclear model.
electrons orbit the nucleus
electrons are at specific distances from the nucleus
Describe how the process of distillation shown in Figure 2 produces pure
water from salt solution.
solution is heated
* water evaporates
allow water boils / vaporises
* the vapour cools in the condenser
* the vapour condenses
or
the vapour turns to a liquid
* (pure) water collects in the beaker
Define mass number.
number of protons plus neutrons
Why is the mass number different in the two isotopes?
(the isotopes contain) different numbers of neutrons
Evidence from the alpha particle scattering experiment led to a change in the model of the atom from the plum pudding model. Explain how. (4)
most (alpha) particles passed (straight) through (the gold foil)
(so) the mass of the atom is concentrated in the nucleus / centre
some (alpha) particles were deflected / reflected
(so) the atom has a (positively) charged nucleus / centre
how to separate Ethanol from ethanol and water
Fractional distillation
how to separate Salt from sea water
Crystallisation
Chadwick’s experimental work on the atom led to a better understanding of
isotopes.
Explain how his work led to this understanding.
Chadwick provided the evidence to show the existence of neutrons
(this was necessary because) isotopes have the same number of
protons
but with different numbers of neutrons
This question is about mixtures and analysis.
(Which two substances are mixtures?
Tick two boxes.
-Air
-Carbon dioxide
-Graphite
-Sodium Chloride
-Steel
Air
Steel
What is the test for chlorine gas
Damp litmus paper turns white