Imagine metal atoms arranged like chocolates in a box, in neat rows. I cut up a piece of lithium the other day and it was bright and shiny, a usual indicator of neat atomic rows. The electrons are all tightly bound, as usual in their shells with the exception of the outermost ones – perhaps one, two or three having no parent atom, which then becomes an ion. The electrons are free to wander about in the metal lattice or scaffolding, occasionally getting captured for a while and looked after by a metal ion, only to break free and change places. These electrons are sometimes called ‘delocalised’. This ‘sea’ of free electrons is what makes metals good conductors of heat and electricity, helps to explain why they are ductile and malleable – meaning that they can be drawn out into wire like copper or beaten into shapes like gold.
The atoms in metals have a strong attractive force between them and a lot of energy is required to overcome it. Therefore, metals often have high boiling points, for example tungsten used to make filaments in lamps, symbol W melts at 5828 K, extremely high.
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