1. (2021八下·黄岩开学考) 默写1~20号元素的符号                                                                                                                                                                                                                                                                                                                                                      

1	2	3	4	5	6	7	8	9	10
	He	Li	Be	B				F	Ne
11	12	13	14	15	16	17	18	19	20
			Si	P			Ar	K