Atomic Structure And The Periodic Table Flashcards
What’s an atom
An atom is the smallest part of an element that can exist. All substances are made of atoms.
How many elements are there?
There are about 100 different elements.
What are compounds formed from?
Compounds have from 2 or more different elements chemically combined in a fixed proportion
What can a compound be separated into?
Compounds can only be separated into elements by chemical reactions
What is a mixture?
A mixture consists of two or more elements or compounds, not chemically bonded together
What’s the charge of an electron?
-1
What’s the relative mass of a neutron?
1
What’s the relative mass of an electron?
Very small or 0
What’s the charge of a neutron?
Neutral or 0
What’s the relative mass of a proton?
1
What does the ‘mass number’ of an atom equal to?
protons + neutrons
What does the ‘atomic number’ of an atom tell you?
The number of protons in an atom has
What’s the charge of a proton?
1
How can you work out how many neutrons an atom has
Number of neutrons = mass number - atomic number
How can mixture be separated by physical processes?
These are physical processes that do not involve chemical reactions and no new substances are made.
- Filtration
- Crystallization
- Simple distillation
- fractional distillation
- Chromatography
Describe and explain filtration? Give examples.
It is used to separate and insoluble solid from a liquid.
Eg. Are useful for separating a mixture of sand and water, or access reactant from a solution. Filtration works because the filter paper has tiny holes or pores in it.
Describe and explain crystallization. Give examples.
A process which helps to separate a pure solid from a solution and it’s crystal form
Eg. The salt we get from seawater can have many impurities in it.
Describe and explain simple distillation. Give some examples.
It is used to separate a solvent from a solution. When the solution is heated the solvent vapor evaporates from the solution. Ex. Pure water from sea water
Describe and explain Fractional distillation. Give examples.
Used to separate different liquids from a mixture of liquids. It is useful for separating ethanol from a mixture of ethanol and water, and for separating different fractions from crude oil
Describe and explain chromatography. Give examples.
used to separate mixtures of soluble substances (separating components of a mixture.) ex. coloured substances such as food colourings, inks, dyes
Before the discovery of electrons, what were atoms thought to be?
Atoms were thought to be tiny spears that could not be divided
What did the discovery of the electron lead to?
It led to the plum pudding, model of the atom
What was the plum pudding Model suggested to be
It was suggested that the atom is a ball of positive charge with negative electrons embedded in it
What was replaced instead of the plum pudding model
The nuclear model