Elements, Atomic structure, Compounds and Mixtures Flashcards
What is an element?
A substance that cannot be broken down into anything simpler. They are made up of only one type of atom. These atoms can either exist individually or bond to other atoms to form molecules
What is a compound?
These substances contain 2 or more elements chemically bonded.The elements are in a fixed ratio shown by the formula and the elements are difficult to separate and need to undergo chemical change if this is to happen.
What is a mixture?
Substances which contain two or more elements/compounds in a variable ratio and which are not chemically combined so they can be separated with relative ease.
What are the physical properties of metals?
Shiny,high melting and boiling points,strong, solid at room temp(exception of 1 metal),malleable,ductile,electrically conductive, thermally conductive
What are the physical properties of non metals?
dull, low melting and boiling points, not strong, solid or liquid or gas at room temp, not malleable, not ductile, not electrically conductive EXCEPT FOR CARBON, not thermally conductive
What is the atomic structure?
There are two main parts- the electron cloud and the nucleus. The nucleus contains protons and neutrons and the number of protons vary with the different elements.
What is the relative mass and charge of a proton?
MASS: 1
CHARGE: 1
What is the relative mass and charge of a neutron?
MASS: 1
CHARGE: 0
What is the relative mass and charge of a electron?
MASS: 1/2000
CHARGE: -1
What is the atomic number?
The number of protons found in the atom.
What is the mass number?
The number of the SUM of protons and neutrons.
How has the Dalton model of an atom changed over time because of the discovery of subatomic particles?
John Dalton stated that
1. Atoms are tiny indivisible particles
2. Atoms of one element are all the same
3. Atoms of different elements are different
4. Compounds are formed by combining atoms
After the discovery of subatomic particles, scientists realised atoms were DIVISBLE.
