A-Level化学例题解析及练习

今日知识点：Ionisation energy and valence electrons

例题

The table gives the successive ionisation energies for an element X.

What could be the formula of the chloride of X

A   XCl

B   XCl2

C   XCl3

D   XCl4

解析

Answer: C

Definition of Ionisation Energy

A  →  A+ + e-

The energy required for the above reaction, or removing an electron. (挪走一个电子需要的能量)

Based on the table, there is a “jump” from the 5th to the 6th ionization energies, so there are 5 valence electrons.

5th 和6th&