C1: Atomic Structure and The Periodic table Flashcards
What is an atom?
The smallest part of an element that can exist
What is an element?
A substance made from only one type of atom
what is a compound?
a substance made of two or more different elements that are chemically combined
what is in the central nucleus?
the central nucleus contains protons and neutrons
what is a proton?
it is a positively charged particle found in the nucleus
what is an electron?
it is a negatively charged particle that orbits the nucleus in outer shells
what is the mass number?
the sum of protons and neutrons in the nucleus
what is the atomic number?
the number of protons in the atom
what is a mixture?
two or more elements or compounds together that are not chemically combined
Define filtration:
separating an insoluble solid from a liquid
Define crystallization:
to separate a solid from a solution
Define simple distillation:
to separate a solvent from a solution
Define fractional distillation:
separating a mixture of liquids, both with different boiling points
Define chromatography:
separating substances that move at different rates through a medium
what is an isotope?
atoms of the same element with the same number of protons but a different number of neutrons
plum pudding model:
a ball of positive charge with negative electrons embedded in it
Geiger and Mardsen’s splitting experiment(4):
- A beam of Alpha particles is directed at a thin foil of gold.
- Most of them went through the foil, proving atoms are mostly empty space
- some were slightly deflected, proving that atoms have a positively charged center
- A minority were completely deflected proving hat there is a dense mass of positive charge in the atom
halogens/ group 7 (4)
- consists of molecules made of a pair of atoms
- have seven electrons in their outer shell and form -1 ions
- melting and boiling points increase down the group
- reactivity decreases down the group
With metals:
Metal + halogen= metal halide
With hydrogen:
Hydrogen + halogen = hydrogen halide
Reacting a halogen with aqueous solution of a halide salt:
The more reactive halogen will displace the less reactive halogen from the salt
Noble gases/ group 0 (4)
- Unreactive
- Do not form molecules due to having full outer shells of electrons
- boiling points increase going down the group
- increasing atomic number down the group
Periodic table(5):
- metals are to the left of the steps
- non metals are to the right
- elements are arranged in order of atomic number
- elements with similar properties are in columns called groups
- elements in the same group have the same number of electrons on the outer shell
Alkali metals/ group 1(5):
- very reactive with oxygen, water and chlorine
- reactivity increases down the group
- Only have one electron on the outer shell
- form + 1 ions
- negative outer electrons are further away from the positive nucleus so they are more easily lost
Alkali metals with oxygen:
Alkali metal + oxygen = metal oxide
Alkali metals with water
Alkali metal + water = metal hydroxide + hydrogen
Alkali metals with chlorine
Alkali metal + chlorine = metal chloride
Mendeleev…
Left gaps for elements that hadn’t been discovered yet
Before the discovery of protons, neutrons and electrons the periodic table had…(2):
- Elements arranged in order of atomic weight
- Early periodic tables were incomplete and some elements were placed in inappropriate groups
