Chemistry

By Kieran

What is a element

• an element, is a material which cannot be broken down or changed into another substance using chemical means.

• There are 117 or 118 known elements.

What is a atom

• All matter is composed of atoms. Each individual atom is composed of three parts: electrons, protons, and neutrons.

• Atoms combine to form elements listed in the Periodic Table.

Metals• In chemistry, a metal is an element, compound, or

alloy characterized by high electrical conductivity. In a metal, atoms readily lose electrons to form positive ions those ions are surrounded by delocalized electrons. The thus produced solid is held by electrostatic interactions between the ions and the electron cloud, which are called metallicbonds.

Non-Metals

• Non-metal, is a term used in chemistry when classifying the chemical elements. On the basis of their general physical and chemical properties, every element in the periodic table can be termed either a metal or a nonmetal. (A few elements with intermediate properties are referred to as metalloids.)

Periodic table• The periodic table is a display of the chemical

elements. It was invented by a Russian chemist named Dmitri Mendeleev in 1869, who intended the table to illustrate recurring trends in the properties of the elements. The layout of the table has been refined and extended over time, as new elements have been discovered, and new theoretical models have been developed to explain chemical behavior.

Compounds• A chemical compound is a pure chemical substance

consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions and that have a unique and defined chemical structure. Chemical compounds consist of afixed ratio of atoms that are held together in a defined spatial arrangement by chemical bonds.

Chemical Reactions• A chemical reaction is a process that leads to the

transformation of one set of chemical substances to another. It can be either spontaneous that is requiring no input of energy or non-spontaneous, that often comes about only after input of some form of energy, viz, heat, light or electricity. Chemical reactions encompass changes that strictly involve the motion of electrons in the forming and breaking of chemical bonds.

Identifying Chemical Reactions

Example Of chemical reaction typeSynthesis means to "put together". A synthesis reaction

is one in which elements or small compounds are combined to make a more complex compound.

some synthesis reactions could include:• 2 Na + Cl2 -> 2 NaCl• SO2 + H2O -> H2SO3• CH2CH2 + HBr -> CH3CH2Br

Physical Chemical ReactionsSome examples of physical changes in chemical

reactions• Sodium is a highly combustible element and

the addition of water can make it explode.• Sodium acetate, when heated and cooled,

becomes supersaturated in water. When it comes in contact with another object it recrystallises. This reaction also causes heat.

3 things that can speed up a chemical reaction

• breaking a solid into something smaller (to increase its surface area)

• make the solution more concentrated, • increase the temperature.

Bibliography

• Wikipedia• Science kids at home• The free dictionary• Chem4kids• list verse• helium