C4 question set 1 Flashcards
Jack writes down some data about the elements in group 7.
melting point boiling point degrees C degrees C Fluorine gas -220 -188
Chlorine gas -101 -35
Bromine liquid -7 -59
Iodine solid 114 184
Jack has made a mistake. One of the boiling points is wrong,
(a) Which boiling point is wrong? Explain how you made your choice [2]
(b) Estimate the correct boiling point [1]
Boiling point for bromine must be wrong as bromine is a liquid at room temperature/ boiling point less than melting point.
Correct boiling point +59 - but a guess between 20 and 150 gets you the mark.
Astatine is another element in group 7. What is the formula for a molecule of astatine?
At2
Use your periodic table for this sort of question, it will tell you the symbol for the new element.
The table shows some information about the element hydrogen.
State at room temperature gas
Type of element non-metal
Atomic number 1
Number of electrons in outer shell 1
Maximum number of electrons outer shell can hold 2
Ion H+
Formula of chloride HCl
Reactivity - very flammable
reacts with metals and non metals
does not react with water
Fay and Guy are discussing where hydrogen fits in the periodic table.
Fay says: Hydrogen is similar to group 1 elements, it should be placed in group 1.
Guy says: I don’t think it fits in group 1, it should be on its own.
Use the information in the table, and your own knowledge of group 1 elements, to evaluate the ideas of Fay and Guy.
The quality of written communication will be assessed in your answer. [6]
Group 1 properties:
Contains metals
Elements are flammable/reactive
Has one electron in the outer shell
Can hold 8 electrons in outer shell
React with water
Only form compounds with non-metals
Fay. Hydrogen fits in group 1 because:
same number of electrons in outer shell
forms an ion with a single positive charge
forms a chloride with similar formula to other group 1 chlorides
very flammable/reactive
reacts with non-metals
Guy: Hydrogen does not fit because:
it is a gas
non-metal
does not react with water
forms compounds with metals
outer shell can only hold 2 electrons
You are only expected to give 2, maybe 3, of the points from each section!
Hydrogen gas reacts with lithium at high temperatures to make lithium hydride.
i. At the high temperatures of the reaction, lithium is a liquid and lithium hydride is a solid.
The equation shows the reaction of lithium with hydrogen.
Fill in the missing state symbols and balance the equation for the reaction.
The state symbols should match the state of the chemicals at the high temperature of the reaction.
lithium + hydrogen -> lithium hydride
….Li( …) + H2 -> LiH
2Li(l) + H2(g) -> 2LiH(s)
The formula for lithium hydride is LiH
What is the formula of the hydride ion?
Put a ring around the correct answer
H2- H- H2- H2+ H+ H2+
H-
A compound has the formula CaH2.
What is the name of this compound?
Calcium hydride
The table below shows the physical properties of some elements.
Appearance at Melting Boiling Conduct
room temp. point point elec?
Chlorine green gas -101 -34 no
Bromine red-brown liquid -7 59 no
Iodine dark grey solid 114 184 no
Lithium shiny solid 180 1341 yes
Sodium shiny solid 97.8 883 yes
Potassium shiny solid 63.5 759 yes
Mendeleev put these elements into two groups in the periodic table.
He used their similarities and differences to put lithium, sodium and potassium in one group.
He put chlorine, bromine and iodine into another group.
Discuss which data in the table support, and which do not support, Medeleev’s idea of organising these elements into two groups.
The quality of written communication will be assessed in your answer. [6]
Group 1.
All are shiny solids.
All conduct electricity.
Melting points and boiling points show a trend within the group of 3..
Group 7.
Do not conduct electricity.
All coloured.
Melting points/boiling points show a trend.
But - points against
Iodine is a solid - high melting point for group.
Lithium has a high boiling point which looks too high for the trend.
Sodium and potassium are both in Group 1 of the periodic table.
Give one similarity and one difference between the arrangement of electrons in an atom of sodium and an atom of potassium. [2]
Both have 1 electron in the outer shell.
Na has 3 shells, K has 4
Liz cuts a piece of sodium with a knife.
When first cut, the surface of the sodium is very shiny.
Describe and explain how the appearance of the sodium changes over the next few minutes.
Tarnishes/goes dull
reacts
with oxygen to produce sodium oxide.
Liz reacts sodium with chlorine to make sodium chloride.
Write a balanced symbol equation for the reaction.
2Na + Cl2 -> 2NaCl
