UC知道化学专业英文 急急急
来源：百度知道 编辑：UC知道 时间：2024/09/22 01:32:21
Each horizontal row of elements constitutes a period. It should be noted that the lengths of the periods vary. There is a very short period containing only 2 elements, followed by two short periods of 8 elements each, and then two long periods of 18 elements each. The next period includes 32 elements, and the last period is apparently incomplete. With this arrangement, elements in the same vertical column have similar characteristics. These columns constitute the chemical families or groups. The groups headed by the members of the two 8-element periods are designated as main group elements, and the members of the other groups are called transition or inner transition elements.
In the periodic table, a heavy stepped line divides the elements into metals and nonmetals. Elements to the left of this line (with the exception of hydrogen) are metals, while those to the right are nonmetals. This division is for convenience only; elements bordering the line—the metalloids-have properties
In the periodic table, a heavy stepped line divides the elements into metals and nonmetals. Elements to the left of this line (with the exception of hydrogen) are metals, while those to the right are nonmetals. This division is for convenience only; elements bordering the line—the metalloids-have properties
（周期表中）每行都是个周期。每个周期的长度不同。有一个周期只有两个元素，接下来是一个有8个元素的周期，再后来两个则分别由18个。再下来就有32个元素了，而且，最后一个周期显然还没有被发现完。按照这样的排列，同竖列的元素有着相似的化学性质。他们统称为族。有着8个元素的周期（1，2，3）中的族被称为主族，而另外的族被称为过渡金属和内过渡金属。周期表内，重金属沿着金属与非金属的分界线排列开来。在这条分界线左边（除了氢）都是金属，而其右为非金属。这样的划分只是为了人为的方便而已。沿着该线的类金属具有金属与非金属共同的特性（如硅，砷等等）。另外，很明显的是绝大部分的元素，包括过渡金属和内过渡金属，都是金属元素。