In general the word periodic describes something that happens at regular (or almost regular) periods. For example, sunrise is periodic because it occurs once per day with a fixed interval between sunrises. The tick of a clock is periodic (one second period). In connection to the periodic table, the word refers to the periodic nature of the properties of the elements as a function of atomic number. So, for example, consider the elements that lie in the second column from the left of the periodic table, the so-called “alkali earth metals”. These elements are Be, Mg, Ca, Sr, Ba and Ra (look them up). All of these elements behave in a similar way, due to the electronic structure of their atoms – react slowly with water to release hydrogen gas – for example. These elements have atomic numbers of 4, 12, 20, 38, 56 and 88, respectively. So, even though the period is not completely regular, you can see that the properties of the elements (react slowly with water) is periodic with atomic number.
Nice answer, Steven.
Drunktinyturtle, let me just add something.
Each row in the Periodic Table is actually called a ‘period’ (although when people talk about them they are still usually referred to as rows), and that is where the name of the table comes from, too (in addition to the periodic nature of properties of the elements, like Steven said). Each column is called a “group” and the elements in each group all have similar chemical properties (as Steven mentioned) because they have the same electron number/arrangement in their outer most electron shell (valence shell). The Periodic Table has all the elements arranged the way that it does so that all the ones with similar properties/reactivity are grouped together in the groups, and the ones together in each period (row) have the same number/type of electron shells. The atomic number (and also size of the atom, and number of protons/neutrons/electrons in the atom) of the elements increases as we go from left to right in the table (across the rows/periods), and from top to bottom (down the columns/groups).
musiclover98
In general the word periodic describes something that happens at regular (or almost regular) periods. For example, sunrise is periodic because it occurs once per day with a fixed interval between sunrises. The tick of a clock is periodic (one second period). In connection to the periodic table, the word refers to the periodic nature of the properties of the elements as a function of atomic number. So, for example, consider the elements that lie in the second column from the left of the periodic table, the so-called “alkali earth metals”. These elements are Be, Mg, Ca, Sr, Ba and Ra (look them up). All of these elements behave in a similar way, due to the electronic structure of their atoms – react slowly with water to release hydrogen gas – for example. These elements have atomic numbers of 4, 12, 20, 38, 56 and 88, respectively. So, even though the period is not completely regular, you can see that the properties of the elements (react slowly with water) is periodic with atomic number.
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Great answer Steven
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Nice answer, Steven.
Drunktinyturtle, let me just add something.
Each row in the Periodic Table is actually called a ‘period’ (although when people talk about them they are still usually referred to as rows), and that is where the name of the table comes from, too (in addition to the periodic nature of properties of the elements, like Steven said). Each column is called a “group” and the elements in each group all have similar chemical properties (as Steven mentioned) because they have the same electron number/arrangement in their outer most electron shell (valence shell). The Periodic Table has all the elements arranged the way that it does so that all the ones with similar properties/reactivity are grouped together in the groups, and the ones together in each period (row) have the same number/type of electron shells. The atomic number (and also size of the atom, and number of protons/neutrons/electrons in the atom) of the elements increases as we go from left to right in the table (across the rows/periods), and from top to bottom (down the columns/groups).
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Well answered so I’ll move on.
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