The periodic table is a tabular organization of the chemical elements based on their atomic number, number of protons in the nucleus, their chemical properties (reactivity for example), and electronic configurations. The structure of the periodic table is perfectly conceived because elements are presented, together with their chemical symbol, in order of increasing atomic number from left to right and from top to bottom. The form of the periodic table consist of a grid in which the elements are organized in 18 columns, called the groups, and 7 lines, termed the periods. Some of the groups have names, for example the first group is called Alkaline metals, the seventh group is called Halogens and the last one, the eighth group, is called noble gases, because of their atomic structure and poor chemical reactivity.
Taking a look at the periodic table, on its left-hand side we find the metallic elements, whereas, proceeding to the right, we first find the transition metals, then the nonmetals and, at the most right-hand side, we find the gases.
The groups are numbered from I to VIII, and these numbers indicated the number of valence electrons of the elements belonging to each group. In other words, an element belonging to the VIth group (for instance, oxygen), has six electrons in tis outs shell. Thus, the nobel gases, which belong to the eighth group, have 8 electrons in their valence shell. Therefore, according to the octet rule, they show poor reactivity with respect to other elements. The chemical reactivity of a given element is strictly related to the number of valence electrons. In a chemical reaction, an element in fact tends to acquire or give a certain number of electrons in order to complete the outer octet and reach the electronic configuration of the preceding or following noble gas. Thus, the elements of the first group, which have only 1 electron in the outer shell, will tend to loose their valence electron and reach the configuration of the preceding noble has (for instance, potassium will loose its electron to reach the configuration of argon).
Plutonium, Our Country's Only Feasible Solution Abstract: Should we begin to manufacture one of the most destructive and infamous substances on the face on the Earth once again? The engineers say yes, but the public says no. The United States stopped making this element with the ban on manufacturing...
Plutonium: 'Our Country's Only Feasible Solution' Abstract: Should we begin to manufacture one of the most destructive and infamous substances on the face on the Earth once again? The engineers say yes, but the public says no. The United States stopped making this element with the ban on manufacturi...
Plutonium, Our Country's Only Feasible Solution Abstract: Should we begin to manufacture one of the most destructive and infamous substances on the face on the Earth once again? The engineers say yes, but the public says no. The United States stopped making this element with the ban on manufacturing...
Abstract This dissertation is attempting to delve into the prevailing attitudes and employee engagement with Topaz South Dublin service stations. The importance of employee engagement is highlighted in relation to the concept of Human Capital Management. The data collection was based on a survey which was carried out by the CIPD (2006) on employee engagement in the UK. The research seeks to understand aspects of working life at the Topaz service stations within the South Dublin catchment area. Aspects such as meaningfulness of tasks within the role, aspects of feelings towards the role, indi...
Abstract This dissertation is attempting to delve into the prevailing attitudes and employee engagement with Topaz South Dublin service stations. The importance of employee engagement is highlighted in relation to the concept of Human Capital Management. The data collection was based on a survey which was carried out by the CIPD (2006) on employee engagement in the UK. The research seeks to understand aspects of working life at the Topaz service stations within the South Dublin catchment area. Aspects such as meaningfulness of tasks within the role, aspects of feelings towards the role, indivi...
Introduction With the end of the Cold War, several domestic conflicts have exploded throughout the world as well as a proliferation in the number of negotiations attempting to settle these conflicts. Many scholars investigating this new phenomena have concluded that there has been a transition fr...