... basic. pH 7 is defined as neutral because it is the pH of pure water at 25 °C4. PLANNING (A) Patterns in the properties of elements. Table 1. Atom Na Mg Ca Al Si P Atomic number 11 12 20 13 14 15 Ionisation energy 494 736 590 577 786 1060 Electro-negativity 0.9 1.2 1.0 1.5 1.8 2.1 Mass of atom 23 24 40 27 28 31 Type of element m m m m nm nm Key: m - metal nm - non-metal On the basis of the table we may clearly see the correlation between atomic number and mass of an atom. Mass of each of the atoms shown above is approximately twice as big as their atomic number. This is thanks to number of protons (atomic number) and nucleons (mass number) in the nucleus. The ionisation energy increases with the group number increasing and period decreasing, however an exception of magnesium has to be marked. Hence, the ionisation energy of aluminium is smaller than that of silicon or phosphorus; the ionisation energy of magnesium is greater than that of calcium. Type of elements also differs in group. Analysing the periodic table, we deduced that going from left to ...

See this essay or coursework document in full right now