Matter and Atom

All matter is made up of elements.
There are 92 elements that occur naturally. The elements hydrogen, carbon, nitrogen and oxygen are the elements that make up most living organisms.
Matter has mass and takes up space.
Atoms are basic building blocks of matter, and cannot be chemically subdivided by ordinary means.The word atom is derived from the Greek word which means indivisible.
Atoms are composed of three type of particles: protons, neutrons, and electron. Both the protons and neutrons reside in the nucleus.
Protons is positive charge, neutrons have no charge and electrons (reside in orbitals around the nucleus) is negative charge.
Protons and neutrons are responsible for the atomic mass (mass number) while the number of protons determines the atomic number.
To know the atomic number and mass number, we can check from periodic table, for example 6C12 means the atomic number is 6 (it has 6 protons), mass number is 12 (it has 6 neutrons).
For exercise : find atomic number and mass number of Freon, Helium, Oxygen, Barium.

The number of protons in an element is constant (e.g. Hydrogen only has 1 proton) but neutron number may vary, which will lead to varied mass number. When the same element may contain varying numbers of neutrons (mass number) ; these forms of an element are called isotopes. Carbon, with atomic number of 6 can have 6, 7, or 8 neutrons (Carbon 12, Carbon 13, Carbon 14)
The chemical properties of isotopes are the same, although the physical properties of some isotopes may be different. Some isotopes are radioactive, they "radiate" energy as they decay to a more stable form.

A condition of which the number of neutron are the same for two elements (which have different atomic number) are called isotones. For example Boron 12 and Carbon 13

When mass number of two elements are equal, we called these elements as isobar. For example Boron 12 and Carbon 12.

Exercise : find isotopes, isotones and isobar of Barium and Calsium

A compound is a stable neutral group of at least two element in a strong bonding.
An ion is an atom or compound which has lost or gained one or more electron.
A mixture is a stable neutral group of at least two atoms or compound in a weak bonding that can separate easily (mostly by physical action).

Exercise : which one molecule, compound, ion, mixture of following :
1. Water
2. Alcohol
3. Acetone
4. Syrop
5. Juice
6. Acetic acid
7. Urea (fertilizer)
8. Urine
9. Cheese
10. Cake

Atomic bond is a strong bond that can not be separated unless a chemical action occurs. There are 2 kinds of atomic bond :
* Ionic bond is a bonding for a positive charged ion to a negative charged ion (usually a bonding consists of metal and nonmetal element, e.g. salt / NaCl)
* Covalent bond is a bonding for nonmetal element e.g. water

Exercise : which one the ionic bond and covalent bond
1. Salt
2. Acid
3. Amonium
4. Lactic acid
5. Nitrogen Compound
6. Base
7. Sugar
8. Rhizobium

Physical changes due to pressure and temperature which will result as a changing of texture, shape, size, color, mass, weight, and density without disturbing the bonding of the components.
Physical changes are reversible, means after they occurred, they can change to the former condition, e.g. shaping log into toys

Physical processes that were trigged by pressure are:
* Filtration uses some apparatus such as filter (paper) and tunnel e.g. to separate sand from seawater
* Injection e.g. to form plastics bead into plastics tray
* Chromatography is a separation of stationary components by moving the other components to other direction e.g. to separate black into its components
* Sedimentation takes a longer time to settle all the bigger density material e.g. water sedimentation from the sand and other deposits
* Centrifugation takes a short time because of the rapid centrifugal force e.g. to separate blood cell from its plasma by centrifuge

Kind of physical processes that were trigged by temperature are :
* Evaporation e.g. to separate salt from salt solution
* Crystallization use heat to separate due to the difference of the boiling point e.g. to crystallize candy
* Distillation use heat to separate due to the difference of the boiling point e.g. to separate kerosene from oil

Chemical changes due to pressure, temperature etc and will lead to changing of bonding. This changes can be observed as a result in gas (bubble), sound (explosion), odor, heat, form (burning), precipitate, decomposition of components.
Chemical changes are irreversible, means after they occurred, they can not be changed, e.g. fermentation of cassava will create lactic acid.