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A chemical reaction occurs when bonds are broken and formed between atoms. Energy is taken in in order to break bonds; when a bond is formed the molecule becomes more stable, so energy is given out. The e...

When elements are heated, it causes their electrons to become excited. Electrons exist in discrete energy levels, and these energy levels are unique to each element. When the electrons are excited by heat...

A transition metal is defined as an element that forms a stable ion with incompletely filled d orbitals. Scandium forms a 3+ ion with no electrons in its d orbitals and zinc forms a 3+ ion with completely...

After the balloon has been blown up with air it increased its size by 0.02 g (Final mass - initial mass = mass of the air).We are told that of oxygen takes up 21% of air. Therefore, we need to work out 21...

Sodium chloride is an ionic compound formed by the strong ionic attractions between positively charged sodium ions (which have lost one electron) and negatively charged chloride ions (which have gained an...