1. An atom is defined as the basic unit of matter which consist of a nucleus and a cloud of negatively charged electrons.
  2. A proton is a positively charged particle and is found in the nucleus of the atom
  3. An electron had a negative charge and surrounds the nucleus
  4. A neutron has no electric charge.
  5. Atomic number is the same as the number of protons in the nucleus
  6. Mass number is equal to the number of protons plus the number of neutrons
  7. Number of neutrons is found by subtracting the atomic number from the mass number
  8. Number of protons is equal to number of electrons in a neutral atom.
  9. The number of particles in one mole of a substance is called Avogadro’s number and is calculated to be 6.02 x 1023
  10. When electrons become excited they move from one energy level to a higher energy level. As the fall back to ground state they emit energy as light and a bright line spectra is produced.
  11. The distribution of an electron in an atom is referred to as the electronic configuration.
  12. Anions are negative ions and is formed when atoms gain electrons
  13. Cations are positive ions and are formed when atoms lose electrons
  14. Elements are pure substances consisting of one or more classes of substances that cannot be broken down into simpler substances by chemical processes.
  15. Isotopes are any two or more forms of an element with same number of protons but different number of neutrons
  16. A solution is a homogenous (same) mixture of two or more substances
  17. Heterogeneous mixtures consist of different, discernable substances and are not uniformed throughout.
  18. A solute is a substance that is being dissolved e.g. salt, while a solvent is the substance (usually liquid) that dissolves the solute e.g. water.
  19. Chemical formulas are written so that the charges on the cation cancel one another.
  20. Coefficients refer to those numbers written in front of products and reactants in order to balance a chemical equation.
  21. Reactants are found on the left side of the reaction arrow and the products are found on the right.
  22. Endothermic reactions absorb the energy from the surrounding while exothermic reactions release energy.
  23. Physical changes refer to the appearance of the material and do no form new substances
  24. Chemical changes result in the formation of new substances
  25. The “Law of Conservation” of energy states that the masses of the reactants in a chemical equation will always be equal to the masses of the products.
  26. There are three states of matter: solid, liquids and gases.
  27. Solids have a definite shape and volume.
  28. The particles in liquids are closely spaced and can easily move alongside each other. They have no definite shape however they have a definite volume.
  29. Gases have widely spaced particles that are in constant random motion and will collide with the walls of the container to create pressure.
  30.  “STP” stands for Standard, Temperature and Pressure.

Now that you are familiar with or have reminded yourself of some of these interesting “MUST KNOWS” in chemistry, wait for Part 2. So while you wait, don’t forget to read a chemistry book, read a chapter, a half of a chapter or even two pages. Just keep the brain fresh with chemistry and your exams will be a breeze!

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