A period 3 element is one of the chemical elements in the third row (or period) of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behavior fall into the same vertical columns. The third period contains eight elements: sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, and argon. The first two, sodium and magnesium, are members of the s-block of the periodic table, while the others are members of the p-block. Note that there is a 3d orbital, but it is not filled until Period 4, such giving the period table its characteristic shape of "two rows at a time". All of the period 3 elements occur in nature and have at least one stable isotope.
Read more about Period 3 Element: Elements, Biological Role, Table of Elements
Famous quotes containing the words period and/or element:
“Stupid word, that. Period. In America it means “full stop” like in punctuation. That’s stupid as well. A period isn’t a full stop. It’s a new beginning. I don’t mean all that creativity, life-giving force, earth-mother stuff, I mean it’s a new beginning to the month, relief that you’re not pregnant, when you don’t have to have a child.”
—Michelene Wandor (b. 1940)
“Beauty is composed of an eternal, invariable element whose quantity is extremely difficult to determine, and a relative element which might be, either by turns or all at once, period, fashion, moral, passion.”
—Jean-Luc Godard (b. 1930)