C2 Flashcards
How are elements ordered in the periodic table?
In order of their atomic weights
How are elements arranged in groups and periods in the periodic table?
Elements with similar properties were put in the same group and they are ordered in order of their atomic weights
Why was the periodic table a breakthrough in how to order elements?
Because before this there was no correct way of ordering elements and no way to properly understand chemical elements.
What is a group in the periodic table?
Vertical columns which contain elements with similar properties.
What is a period in the periodic table?
The horizontal rows in a periodic table.
How does electronic structure in group 1,2 and 3 link to the periodic table?
Because group 1,2 and 3 on the periodic table have to lose electrons to attain the electronic structure of the noble gases.
Are noble gases reactive or unreactive?
Unreactive
Compare the electronic structure of a metal and non metal
Metals conduct electricity but non metals are usually electrical insulators. Exceptions are some forms of carbon. In general, metals also have much higher melting and boiling. Metals are ductile and malleable, whereas non metals solids are brittle.
Why are noble gases unreactive?
They are monatomic (single-atom) gases. So they have no tendancy to react and modify their electronic structures by forming molecules.
Explain the noble gases trends in their boiling points
The boiling points get higher going down group 0. Helium at the top boils at -269°C whereas radon,at the bottom boils at -62°C.
Name the first three elements in group 1
Lithium (Li), sodium (Na) and potassium (k)
Do they group 1 metals have low or high densities?
Low densities
Write a word equation of how a group 1 metal reacts with water
Sodium + water – sodium hydroxide + hydrogen
Explain why the first three group 1 elements float on water
The water reacts with the metal to form hydrogen gas. Potassium reacts so vigorously with water that the hydrogen produced ignites. It burns with a lilac flame, coloured by the potassium ions formed in the reaction.
How can you show that hydrogens and metal hydroxides are made when group 1 metals react with water?
They are called alkali metals because they also produce a metal hydroxide when reacting with water. The hydroxides of alkali metals are all soluble in water. This solution is colourless with a high pH.
What safety precautions have to be taken when dealing with group 1 metals?
They are to be stored in oil which stops them reacting with oxygen in the air.
How do group 1 metals form ions with a +1 charge when they react with non-metals? (Optional question, very long answer, will probably help in the exam though)
They react vigorously with non-metals such as chlorine gas, which produce metal chlorides, which are white solids. The metal chlorides all dissolve readily in water to from colourless solutions. Reactions get more vigorous as you go down the group. Because it becomes easier to lose the single electrons in the outer shell to form ions with a +1 charge. They react in a similar way with fluorine, bromine and iodine. The solutions formed are all colourless.
Name the first 4 elements in group 7
Fluorine, chlorine, bromine and iodine
Describe the main properties of halogens
They have low melting points and boiling points. Their melting and boiling points increase going down the group.
They are poor conductors of heat and electricity.
Explain why elements in group 7 react similarly
Because they all have 7 electrons in their outermost shell and their electronic structure determines the way they react with other elements.
What is the trend in reactivity in group 1?
Get more reactive going down the group
What is the trend in reactivity in group 7?
The elements get less reactive going down the group
How does electronic structure affect the trend of group 1 elements?
Because the atoms get larger so the single electron in the outermost shell (highest energy level) is attracted less strongly to the positive nucleus. The electrostatic attraction with the nucleus gets weaker because the distance between the outer electron and the nucleus increases.
How does the electronic structure affect the trend in reactivity in group 7?
When group 7 elements react their atoms gain an electron in their outermost shell. Going down the group the outermost shell’s electrons get further away from the attractive force of the nucleus, so it is harder to attract and gain an extra incoming electron.
