B. 和的质子数相同，互称同位素

A. 和的质量数相同，互称为同位素

1. 金属钛对人体体液无毒且惰性，能与肌肉和骨骼生长在一起，有“生物金属”之称。下列有关和的说法中正确的是                                               

21．（8分）

⑴                                                                      

(2）                              

(3)                                

(4)                                

请在各题规定的矩形区域内答题，超出该区域的答案无效!

宁乡县2008年下学期期末调研考试高中三年级

20．（12分）

(1):                                                                     

(2)                                                                      

(3)                                                                     

19．（8分）

( 1 )               

( 2 )                                                                     

(3)               

(4)               

18．（10分）

⑴                                                                        

(2)                                                                     

(3)　　　　　　                                                         

(2)                               

(3)                                                                   

请在各题规定的矩形区域内答题，超出该区域的答案无效!

17．（7分）

(1)　　　                                      　

16．（10分）

(1)                          

 (2)                                                                    

(3)                                

(4)