Write true or false for the following statements:

The term atomic size refers to the distance between the centre of the nucleus and the penultimate shell of an isolated atom.

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In 1913, Dmitri Ivanovich Mendeleev showed that the atomic number of an element is a more fundamental property than its atomic mass.

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Na, Mg, Li, Al, Si, F, P and Cl belong to the third period of the Modern periodic table.

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In the Modern periodic table, a zig-zag line separates metals from non-metals. The borderline elements-boron, silicon, germanium, arsenic, antimony, tellurium and polonium are intermediate in properties and are called metalloids or semimetals.

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Metallic character decreases across a period and increases down a group because the effective nuclear charge acting on the valence shell electrons increase across a period and decreases down the group.