Elements and the limestone cycle Flashcards
Describe 3 points about an atom’s nucleus. ..
It’s in the middle if the atom
It contains protons and neutrons Protons are positively charged and neutrons have no charge
The nucleus is positively charged overall
It’s tiny compared to the size of the atom
Describe the electrons in 4 points …
They move around the nucleus they're negatively charged they're tiny but cover a lot of space they occupy shells around the nucleus The shells explain the whole of chemistry
Number of protons = the. …
The charge is always. …
Number of electrons Equal and opposite to the electrons
If electrons are added or taken away what is the atom called?
An ion
What decides what type of atom it is?
The number of protons
If a substance contains onettle of atom it’s called an …
Element
How are elements grouped?
Ones with similar properties are in the same groups
What are the vertical columns called?
Why do the elements have similar properties?
Groups
They have the same number of electrons in their outer shell
What is the top number next to the element symbol?
The mass number
Atomic number - proton number
Electrons are always on…
Atoms are stable when they have…
If they are unstable they have… so they are….
shells
full electron shells
under 8 electrons on their outer shell (or 1, hydrogen)
they are reactive
number of protons =
number of electrons
What is the electronic structure for Nitrogen?
It has to inside ring electrons, then 5 on the outside.
2,5
What bond does a compound have if there is a metal in it? What are the atoms like?
And if there’s no metal atom?
Ionic, ions
Covalent
What compound is limestone mostly made up of?
CaCO3 - calcium carbonate
What is thermal decomposition?
When a substance chemically changes into at least two different products when heated.
What does calcium carbonate thermal decompose into?
calcium oxide and carbon dioxide
Why can’t you thermally decompose group 1 metal carbonates in the class room?
The bunsen burner doesn’t reach high enough temps.
What does calcium carbonate + sulphuric acid make?
Calcium sulphate salt, CO2 and water.
What does calcium oxide (quick lime) + water =?
Calcium hydroxide - slaked lime
What is calcium hydroxide (slaked lime) used for? (2)
Neutralising acidic soil in fields - it works faster than powdered limestone.
To test for CO2, if made into a solution, lime water, bubble the gas through it and the solution will turn cloudy if CO2 is present.
Calcium hydroxide + CO2=
Calcium carbonate and H2O
How is cement made?
Powdered limestone is heated in a kiln with powdered clay to make it.
How is mortar made?
Cement can be mixed with sand and water to stick bricks together, you can also add calcium hydroxide to cement to make it.
How is concrete made?
Mix cement with sand and aggregate