Page 36 - Curriculum Visions Dynamic Book

The reaction of acids with metals
The reaction of acids with metals is often referred to as corrosion. It is an extremely important reaction. It is also a very good demonstration of the use of the Periodic Table (see page 46).
Metals are on the left of the Periodic Table. They have one, two or three more electrons than the nearest inert gas. When metals react (corrode) they lose these outer shell electrons and become positively charged ions.
Each electron lost means one
more positive charge on the ion.
For example, sodium (Na+) has lost one electron, magnesium (Mg2+) has lost two and aluminium (Al3+) three.
For these metals to react,
the “lost” electrons have to be accepted by some other substance. Hydrogen ions (H+, produced by acids in water) can readily accept electrons, turning hydrogen ions into hydrogen molecules.
Each hydrogen ion gains one electron to become a hydrogen atom and then two hydrogen atoms share their electrons to become a hydrogen molecule and thus form hydrogen gas.
Some examples of reactions between metals and acids are shown on these two pages.
Zinc
Sulphuric acid
 For a metal to react in such a way as to release hydrogen gas the metal has to be above hydrogen in the reactivity series.
REACTIVITY SERIES
Element
Reactivity
potassium sodium calcium magnesium aluminium manganese chromium zinc
iron cadmium tin
lead hydrogen copper mercury silver gold platinum
most reactive
least reactive
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