7. Comparison of the original Mendeleef type of periodic table
(Figure 1.2} and the modern periodic table (p. (/)) shows that the
original group numbers are retained but Group I, for example, now
contains only the alkali metals, i.e. it corresponds to the top two
Group I elements of the Mendeleef table together with Group I A. At
the other end of the table, Group VII now contains only the halogens,
i.e. the original Group VIIB. The transition elements, in which the
inner d orbitals are being filled, are removed to the centre of the table
and the "rare earth' elements, in which the^/ orbitals are being filled,
are placed, for convenience, at the bottom of the table, eliminating
the necessity for further horizontal expansion of the whole table.
The original lettering of the transition metal groups, for example
VIB, VIIB and so on is still used, but is sometimes misleading and
clearly incomplete. However, we may usefully refer, for example, to
7. Comparison of the original Mendeleef type of periodic table(Figure 1.2} and the modern periodic table (p. (/)) shows that theoriginal group numbers are retained but Group I, for example, nowcontains only the alkali metals, i.e. it corresponds to the top twoGroup I elements of the Mendeleef table together with Group I A. Atthe other end of the table, Group VII now contains only the halogens,i.e. the original Group VIIB. The transition elements, in which theinner d orbitals are being filled, are removed to the centre of the tableand the "rare earth' elements, in which the^/ orbitals are being filled,are placed, for convenience, at the bottom of the table, eliminatingthe necessity for further horizontal expansion of the whole table.The original lettering of the transition metal groups, for exampleVIB, VIIB and so on is still used, but is sometimes misleading andclearly incomplete. However, we may usefully refer, for example, to
การแปล กรุณารอสักครู่..
