①2H ②Al3+ ③
![](https://img./dksih/QBM/2021/7/8/2759633300021248/2759790396760064/STEM/4d35665d14ac4304af4fe6e61c004257.png?resizew=62)
![](https://img./dksih/QBM/2021/7/8/2759633300021248/2759790396760064/STEM/a54145ef5f124e32bf95971de0eec79f.png?resizew=89)
A.①表示2个氢分子 |
B.②表示铝元素的化合价为+3价 |
C.③表示镁原子的结构示意图 |
D.由④可知铕的原子序数为63 |
![](http://static.xuejinqu.com/images/y-prise.png)
同类型试题
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y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
![](http://static.xuejinqu.com/images/avatar.png)
![](http://static.xuejinqu.com/images/avatar.png)
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
![](http://static.xuejinqu.com/images/avatar.png)
![](http://static.xuejinqu.com/images/avatar.png)