元素周期表的趋势

元素的物理、化学性质随原子序数逐渐变化的规律叫做元素周期律。元素周期律由门捷列夫（Dmitri Mendeleyev）首先发现，并根据此规律创制了元素周期表。

结合元素周期表，元素周期律可以表述为：

注意：以上规律不适用于稀有气体。

此外还有一些对元素金属性、非金属性的判断依据，可以作为元素周期律的补充：

还有一些根据元素周期律得出的结论：

In chemistry, the Periodic Law states that if the chemical elements are listed in order of increasing atomic number, many of their properties go through cyclical changes, with elements of similar properties recurring at intervals. For example, after arranging elements in their increasing atomic numbers, many of the physical and chemical properties of Lithium are recurred into Sodium such as its vigorous reactivity with water, which again recurs in the next cycle starting with Potassium.