read the text again and fill in the gaps with a suitable word from the boxes in each part

properties elements opaque chemical periodic rust conducts materials

this (1) element is a good conductor of both electricity and heat. in chemistry, this (ancient greek métallon, μέταλλον) is an element or alloy that (2) electricity. in this element, atoms readily lose electrons to form positive ions. those ions are surrounded by delocalized electrons, which are responsible for the conductivity.

metals occupy most of the periodic table, while non-metallic (3) can only be found on the right-hand-side of the (4) table of the elements. a diagonal line drawn from boron (b) to polonium (po) separates the metals from the non-metals. most elements on this line are metalloids, sometimes called semiconductors. this is due to the fact that these elements have electrical (5) common to both conductors and insulators (elements that don’t carry electricity). elements to the lower left of this division line are called metals, while elements to the upper right of the division line are called ( .

metals are very corrosive – they (7) in contact with water. painting (or any other form of covering) is a good way to prevent their corrosion.

metals in general have high electrical conductivity, the ability to be deformed under stress. optically speaking, metals are (8) (that means ‘not clear’), shiny and lustrous. the large number of free electrons in any typical metallic element or alloy is responsible for the fact that they can never be categorized as transparent (9) .