The Element Lithium - Structure and Properties
All isotopes of this element behave exactly the same way in chemical reactions since all Lithium atoms have, in their neutral state, three electrons. That's one electron for each proton, one negative charge for each positive charge. The two naturally occurring isotopes of Lithium are 6-Lithium and 7-Lithium. These are atoms that have 3 and 4 neutrons in the nucleus respectively, and they can be represented as follows: 
7-Lithium is the most common of these two forms, making up 92.5% of the Lithium atoms in a sample, on average. 6-Lithium makes up the remaining percentage. There are several other known isotopes of Lithium including 4-Lithium (1 neutron), 8-Lithium (5 neutrons) and 9-Lithium (6 neutrons). All these isotopes are extremely short lived. The Lithium Ion Lithium has a full 1s (sub)shell and one electron in its second shell, in the 2s subshell. Since elements are stable with eight electrons in the outer shell, Lithium must either gain 7 electrons or lose 1 in order to achieve this. Since the Lithium nucleus does not have enough charge to attract a further seven electrons, it tends to lose its 2s electron to achieve stability. 
This gives an element lithium atom with an overall balance of +1 since there is now one more proton than there are electrons. A diagram of this is shown at the right. This is called a positive ion. The little superscripted 1 is the amount of positive charge, and the sign shows positive or negative. This is the standard was of describing charged ions. This state is very stable for Lithium. It is so stable that Lithium is only ever found in this ionic form in nature. It is never encountered as a metal, though it is possible to manufacture Lithium metal through electrolysis of molten Lithium salts. The metal that is produced is silvery gray and extremely reactive, though less so than the metals of the other elements in Group 1 of the Periodic Table. It needs to be stored away from contact with air and water. Uses of Lithium When Lithium metal reacts in batteries, the electric charge it gives off is of a high voltage which is why these are a preferred metal in many single use and rechargeable power cells. Lithium metal can also be combined with other metals to produce lightweight and strong alloys. The element Lithium is also used in medical applications as a mood stabilizer as well as serving many other functions.
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