Chemistry

Chemistry

1. What atoms are and their structure

   • Atomic structure All material things are made from atoms. There are just over one hundred different types of atom, called elements. Atoms can join together in millions of different combinations to make all the substances on Earth
   • Every atom is made of a nucleus consisting of protons and neutrons. The nucleus is surrounded by electrons. Protons and electrons are oppositely charged. Neutrons have no charge. This means the nucleus of an atom is always positively charged

2. Isotopes.

   • Isotopes are atoms of an element with the normal number of protons and electrons, but different numbers of neutrons. Isotopes have the same atomic number, but different mass numbers. The different isotopes of an element have identical chemical properties.

3. Subscript and superscript

   • A subscript or superscript is a character (number, letter or symbol) that is (respectively) set slightly below or above the normal line of type. It is usually smaller than the rest of the text. Subscripts appear at or below the baseline, while superscripts are above. Subscripts and superscripts are perhaps most often used in formulas, mathematical expressions, and specifications of chemical compounds and isotopes

4. Mixtures and how to separate them.

   • SEPARATING MIXTURES. The substances in a mixture are separated by the differences in their physical properties, such as their particle size. The more different the properties are, the easier it is to separate the substances. Tea leaves do not dissolve in water, so you can use a strainer to FILTER them

5. Models of the atom (nuclear and plum pudding).

   • Rutherford's model did not completely reimagine Thomson's. Like Thomson, Rutherford still believed that atoms contained negatively charged electrons. Unlike the plum pudding model, where those atoms simply floated in "soup," Rutherford believed they orbited the central nucleus just as planets orbit the sun.

6. Periodic table

   • The periodic table is a tabular arrangement of the chemical elements, ordered by their atomic number (number of protons), electron configurations, and recurring chemical properties. This ordering shows periodic trends, such as elements with similar behaviour in the same column