![periodic table of elements valence electrons periodic table of elements valence electrons](https://image2.slideserve.com/5236233/valence-electrons-l.jpg)
The transition elements, on the other hand, lose the ns electrons before they begin to lose the ( n – 1) d electrons, even though the ns electrons are added first, according to the Aufbau principle. As a general rule, when the representative elements form cations, they do so by the loss of the ns or np electrons that were added last in the Aufbau process. Lithium has a single electron in the second principal. In the second period elements, the two electrons in the 1 s sublevel are called inner-shell electrons and are not involved directly in the elements reactivity, or in the formation of compounds. The electron dots in the Lewis structure are a convenient way to determine how many bonds an atom of an element can make. 1: Lewis symbols or electron-dot symbols of the first twenty elements in the periodic table. Thus, as we would expect, the outermost or valence electrons are easiest to remove because they have the highest energies, are shielded more, and are farthest from the nucleus. Valence electrons are the electrons in the highest occupied principal energy level of an atom. Helium is an exception that has only two valence electrons, but they are shown paired. The locations of period 4 and period 5 transition elements are provided with green dots. Similarly, minima exist at the locations of noble or inert gases: H e, N e, A r, K r, X e, and R n. Peaks are evident at the locations of the alkali metals: L i, N a, K, R b, and C s.
![periodic table of elements valence electrons periodic table of elements valence electrons](https://image.slidesharecdn.com/valenceelectrons-120524145827-phpapp01/95/valence-electrons-8-728.jpg)
A black jagged line connects the radii values for elements with atomic numbers 1 through 60 on the graph. This graph is labeled Atomic Number on the horizontal axis and Radius (p m) on the vertical axis. Within each group (e.g., the alkali metals shown in purple), the trend is that atomic radius increases as Z increases. \): Within each period, the trend in atomic radius decreases as Z increases for example, from K to Kr.