Shield example sentences

This happens because the inner energy levels are filled with electrons, which serve to shield the outer electrons from the pull of the nucleus.Therefore, it is important to maintain the ozone shield.The penetration of a 2s-electron to the nucleus is more than that of a 2p-electron; hence the 2p electron of boron is more shielded from the nucleus by the inner core of electrons than the 2s electrons of beryllium.For example, the 2s electron in lithium is shielded from the nucleus by the inner core of 1s electrons.The effective nuclear charge experienced by a valence electron in an atom will be less than the actual charge on the nucleus because of shielding or screening of the valence electron from the nucleus by the intervening core electrons.As we go down a group, the outermost electron being increasingly farther from the nucleus, there is an increased shielding of the nuclear charge by the electrons in the inner levels.As a result, the valence electron experiences a net positive charge which is less than the actual charge of + In general, shielding is effective when the orbitals in the inner shells are completely filled.Thus, across a period, increasing nuclear charge outweighs the shielding.When we move from lithium to fluorine across the second period, successive electrons are added to orbitals in the same principal quantum level and the shielding of the nuclear charge by the inner core of electrons does not increase very much to compensate for the increased attraction of the electron to the nucleus.However, down the group, due to poor shielding effect of intervening d and f orbitals, the increased effective nuclear charge holds ns electrons tightly (responsible for inter pair effect) and thereby, restricting their participation in bonding.Iron ore, nickel, gold, uranium and copper are mined in the Canadian Shield Region, coal in the Appalachians region.As a result, the valence electron experiences a net positive charge which is less than the actual charge of + In general, shielding is effective when the orbitals in the inner shells are completely filled.When we move from lithium to fluorine across the second period, successive electrons are added to orbitals in the same principal quantum level and the shielding of the nuclear charge by the inner core of electrons does not increase very much to compensate for the increased attraction of the electron to the nucleus.In this case, increase in shielding outweighs the increasing nuclear charge and the removal of the outermost electron requires less energy down a group.Small decrease in ?iH from Si to Ge to Sn and slight increase in ?iH from Sn to Pb is the consequence of poor shielding effect of intervening d and f orbitals and increase in size of the atom.