Elements and compounds

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Organising of chemical elements:

There are 110 elements that are named and some are yet to be named.

92 of them until uranium occur naturally.

The rest are artificial and are only found in special situation like in nuclear labs and do not last long.

Th International Union of Physics and Applied Chemistry (IUPAC) is responsible for naming elements and the compounds they form.

elements can be named after their name itself or after their greek or latin origin.

They can be classified into metals and non-metals in standard lab condition.

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Periodic table

Organises elements into their increasing atomic number.

The horizontal rows are called periods. There are 7 periods.

The vertical columns are called groups. They are numbered in roman numerals from 1-8. They are similar chemically and in their reactivity.

Eg: Elements of the first group are called alkali metals. they are highly reactive with oxygen and water and become +1 ions.

Elements of group VII are called halogens and they have similar properties too. Eg: they become -1 ions when ionically compounded.

The groupVIII elements are called noble gases as they are unreactive.

Transition metals form a transition between metals and non-metals. They have complex properties because of the arrangement of electrons in the cloud.

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Chemical compounds:

They are formed when to atoms chemically combine to form molecules or lattices.

It occurs as a result of chemical reaction.

FORMULAS FOR COMPOUNDS:

The chemical formula for compounds usually show the number of atoms of each elements each contains or for a lattice, the ratio of the number of atoms of each element.

The names of compounds may directly reflect what they contain or might be historically significant.

Organic compounds include substances that have carbon as the backbone to their molecule, e.g.:methane and DNA. They are grouped according to different types and groups of elements they belong to.