— I think John is ______ than Bill and Tom.
A:the most serious; more serious
B:the most serious; serious
C:serious; more serious
D:more serious; more serious
下列说法中错误的是( )
氢原子基态能量E1=﹣13.6eV,电子绕核运动半径r1=0.53×10﹣10m.En= E1n2 ,rn=n2r1求氢原子处于n=4激发态时:(电子的质量m=0.9×10﹣30kg)
从海陆分布角度来看,我国属于( )