第一节　原子结构1.1999年是人造元素丰收年 ,一年间得到了核电荷数分别为 114、116、118三种新元素。已知核电荷数为 118的新元素的一种原子的质量数为 2 93,则该原子里中子数与电子数之差为 (　　 )。A .0　　B .5 7　　C .118　　D .1752 .A、B两种原子 ,A的M电子层比B的M电 Section 1 Atomic Structure 1. 1999 was a year of harvest of man-made elements. In the year, the nuclear charge numbers were 114, 116, and 118 new elements. It is known that the mass number of an atom of a new element with a nuclear charge number of 118 is 2,93, and the difference between the number of neutrons and the number of electrons in this atom is (). A .0 B .5 7 C .118 D .1752 .A, B two kinds of atoms, A M electronic layer than B M electric