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
What is always different for atoms of different elements?
number of protons
Describe, as fully as you can, what happens when sodium reacts
with fluorine to produce sodium fluoride.
sodium (atom) loses
fluorine (atom) gains
one electron
ions formed
Why does pure water not conduct electricity?
no delocalised / free electrons
Explain why the reactivity of elements changes going down Group 1.
reactivity increases (going down the group)
(because) the outer electron / shell is further from the nucleus
(so) there is less attraction between the nucleus and the outer
electron / shell
(so) the atom loses an electron more easily
Going down Group 7 the melting points _______________
increase
Explain the trend in boiling points of the halogens shown in Table 1.
boiling point) increases (down the table / group)
(because) the relative formula / molecular mass increases
(so) the intermolecular forces increase (in strength)
(so) more energy is needed to overcome the intermolecular forces
Why did Mendeleev’s periodic table become more widely accepted than
previous versions?
Mendeleev had predicted properties of missing elements
elements were discovered (that filled the spaces / gaps)
properties (of these elements) matched Mendeleev’s predictions
Sodium is in Group 1 of the modern periodic table.
Describe what you would see when sodium reacts with chlorine.
-flame
-(white) solid forms
- colour of gas / chlorine disappears / fades
Evaluate Newlands’ and Mendeleev’s tables.
You should include:
* a comparison of the tables
* reasons why Mendeleev’s table was more acceptable.
comparative points
*both tables have more than one element in a box
both have similar elements in the same column
*both are missing the noble gases
*both arranged elements in order of atomic weight
Newlands did not leave gaps for undiscovered elements
*Newlands had many more dissimilar elements in a column
Mendeleev left gaps for undiscovered elements
*Mendeleev changed the order of some elements
*Mendeleev predicted properties of missing elements
elements with properties predicted by Mendeleev were discovered
Mendeleev’s predictions turned out to be correct
elements were discovered which fitted the gaps
Give one limitation of using a dot and cross diagram to represent an
ammonia molecule.
does not show the shape
or
only two-dimensional
Suggest why the reaction in Stage 2 is carried out in an atmosphere of
argon and not in air.
argon is unreactive / inert
oxygen (from air) would react with sodium / titanium
compare the
chemical and physical properties of transition elements and Group 1
elements.
Physical
Transition elements
* high melting points
* high densities
* strong
* hard
Group 1
* low melting points
* low densities
* soft
Chemical
Transition elements
* low reactivity / react slowly (with water or oxygen)
* used as catalysts
* ions with different charges
* coloured compounds
Group 1
* very reactive / react (quickly) with water / non-metals
* not used as catalysts
* white / colourless compounds
* only forms a +1 ion
How can you tell that a chemical reaction is taking place?
there was a flame
* energy was given out
* a new substance was formed
Give one disadvantage of using nanoparticles in sun creams.
- Potential cell damage to the body
- Harmful effects on the environment
A student tested a metal chloride solution with sodium hydroxide solution.
A brown precipitate formed.
What was the metal ion in the metal chloride solution?
Iron(III)
Explain why octane is a hydrocarbon.
contains hydrogen and carbon
(hydrogen and carbon) only
Explain how a covalent bond holds two atoms together.
electrostatic force of attraction between shared pair of negatively charged electrons
and both positively charged nuclei
Would collecting and plotting data for more sizes of nanoparticles improve the
conclusions?
(no) because trend / conclusion is already clear
