The periodic table, Ions (tests, compounds, precipitates) Flashcards
The atomic number is also the same as the _______ number.
Proton.
The atomic mass is _______ + ________.
Protons + Neutrons.
What is meant by atomic mass?
The mass in relation to carbon-12.
True or false:
The pre-mendelev periodic table had gaps.
False.
What do the groups in the periodic table represent?
Number of electrons on the outermost shell and that the elements have similar chemical properties.
What do the periods represent?
The number of electron shells an element has.
What is an isotope?
Same number of protons but a different number of neutrons.
Name 4 characteristics of the pre-mendelev periodic table.
- There were no gaps (they assumed they found all the elements).
- The elements were ordered in terms of mass.
- There were not many elements.
- Chemical properties were not considered.
What are the differences between the pre-mendelev table and the modern one?
- Elements on the MPT where arranged in the order of RAM and not of mass.
- Properties were considered in the MTP but not on the pre-mendelev table.
- Mendelev left gaps for other elements that hadn’t been discovered yet but the pre-mendelev one had no gaps.
What is meant by an ion?
An atom with a charge.
What are cations?
Positively charged atoms.
What are anions?
Negatively charges ions.
Metal atoms lose electrons to form ______.
Cations.
Non-metal atoms gain electrons to form______.
Anions.
When a compound ends in ‘-ate’ what can this tell you?
That oxygen is part of the compound.
Name 4 properties of ionic compounds.
- High melting points.
- High boiling points.
- They are soluble.
- Can conduct electricity when molten or aqeous only.
All common salts of _____, ________, and _________ are soluble in water.
(Remember: SPA)
Sodium, potassium and ammonium.
What 2 chlorides cannot dissolve in water?
(Remember: Sledge hammer)
Silver and lead.
What 3 sulfates cannot dissolve in water?
(Remember: LBC 97.3 or PbBaCa)
Lead, Barium and calcium.
Most __________ and ___________ are insoluble in water (with the exceptions of SPA).
Carbonates, hydroxides.
How would you prepare a salt from 2 solutions? (4)
- Mix the 2 solutions.
- Filter the mixture.
- Wash the insoluble salt with water.
- Leave to dry.
Why is barium sulfate safe to swallow even though it’s toxic?
It’s insoluble, so it will not dissolve into the blood and cause harm.
Name the colour of the flame for the following ions:
- Sodium
- Postassium
- Calcium
- Copper
- Yellow
- Lilac
- Brick red
- Green-blue
How would you test for carbonate ions?
- Add dilute acid to the substance.
- Test the gas given off using limewater.
If the substance contains carbonate ions:
- It will fizz or bubble as the gas is given off.
- It would turn the limewater cloudy showing the gas is carbon dioxide.
How would you test for sulfate ions?
- Add a few drops of dilute HCl.
- Shake the mixture.
- Add a few drops of barium chloride to the solution.
If the substance contains sulfate ions a white precipitate of barium sulfate will form.
How would you test for chloride ions?
- Add a few drops of nitric acid.
- Shake the mixture.
- Add a few drops of silver nitrate to the solution.
If the substance contains chloride ions a white precipitate of silver chloride forms.
Why do ionic substances have high melting and boiling points? (3)
- There are strong electrostatic forces between the particles are the ionic bonds.
- It takes a lot of energy for these bonds to be broken.
