Mercury, orbital period

The density estimates in Table 7.1 show a distinction between the structures of the planets, with Mercury, Venus, Earth and Mars all having mean densities consistent with a rocky internal structure. The Earth-like nature of their composition, orbital periods and distance from the Sun enable these to be classified as the terrestrial planets. Jupiter, Saturn and Uranus have very low densities and are simple gas giants, perhaps with a very small rocky core. Neptune and Pluto clearly contain more dense materials, perhaps a mixture of gas, rock and ice. 

For Mercury, long imagined on the basis of optical observations to rotate once per 88-day revolution around the Sun, radar bandwidth measurements (see Fig. 6) demonstrated direct rotation with a period (59 days) equal to two-thirds of the orbital period. This spin-orbit coupling is such that during 2 Mercury years, the planet rotates three times with respect to the stars but only once with respect to the Sun, so a Mercury-bound observer would experience alternating years of daylight and darkness. 

However, deviations from straightforward extrapolations within the Periodic Table were also considered [19]. As a consequence of relativistic effects on the electronic structure, the, v- andp-orbitals of heavy elements should shrink whereas higher lying orbitals should expand. Consequently, the two, v electrons in element 112 and also the two pm electrons in element 114 could form closed electron shells, and eka-mercury and eka-lead could both be chemically inert gases like element 118, eka-radon. 

Ge, As, Se, Br, and Kr). Zinc, cadmium, and mercury are often classified as main group elements. The periodic table is divided into blocks. The s-block elements have valence configuration si or s2. The p-block elements have valence configuration slpl to s2p6. The d-block and /-block elements usually have two electrons in the outermost s-orbital but have partially filled d or f subshells in an inner orbital. 

The /-transition metals are located between Groups HA and IflA in the periodic table. Strictly speaking, a /-transition metal must have a partially filled set of d orbitals. Zinc, cadmium, and mercury (Group IIB) and their cations have completely filled sets of d orbitals, but they are often discussed with /-transition metals because their properties are similar. All of the other elements in this region have partially filled sets of d orbitals, except the IB elements and palladium, which have completely filled sets. Some of the cations of these latter elements have partially filled sets of d orbitals. 

The amount of time a planet takes to complete one orbit of the Sun increases as the distance from the Sun increases. This value, called the sidereal period, ranges from 0.241 years for Mercury to 248.1 years. 

The element belongs to the large group of transition elements or d block. The position within the Periodic Table of the elements is below zinc and above mercury. The zinc group has a filled d ° orbital and is transitional between the d block and the p block elements of boron and others. The outer electronic configuration of the zinc group is d S and the common oxidation state is -i- II. 

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