已知短周期主族元素X、Y、Z在元素周期表中的位置如下图，
下列说法正确的是
| A．原子半径Y＞X＞Z |
| B．X元素一定是非金属元素 |
| C．当X、Y、Z为非金属时，气态氢化物的稳定性：Y＞X＞Z |
| D．Z的原子序数可能是X的原子序数的2倍 |
相关试题
It is often ______ that human beings are naturally equipped to speak.
| A．said | B．to say | C．saying | D．being said |
I can’t leave. She told me that I ______ stay here until she comes back.
| A．can | B．must | C．will | D．may |
—— Do you mind my opening the window? It’s a bit hot in here.
—— ______ , as a matter of fact
| A．Go ahead | B．Yes, my pleasure |
C．Yes, I do | D．Come on |
It’s high time you had your hair cut ; it’s getting _______ . 
| A．too much long | B．much too long |
C．long too much | D．too long much |
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