已知A元素原子的L层比B元素原子的L层少3个电子，B元素原子的核外电子总数比A多5个，则A与B可形成（）。

Project（71）is an uncertain event or condition that，if it occurs，has a positive or a negative effect on at least one project objective，such as time，cost，scope，or quality．

Project ______is an uncertain event or condition that，if it occurs，has a positive or a negative effect on at least one project objective，such as time，cost，scope，or quality．

● Project（71）is an uncertain event or condition that, if it occurs, has a positive or a negative effect on at least one project objective, such as time, cost, scope, or quality.（71）

下列电子构型属于原子基态的是（　　）。

原子序号为24的元素的基态原子，其核外电子排布为（　　）。

某原子序数为15的元素，其基态原子的核外电子分布中，未成对电子数是（　　）。[2017年真题]

下图是N、O、F三种元素基态原子电子排布的轨道表示式。试回答下列问题： 画出C原子基态原子电子排布的轨道表示式。

氩（Z＝18）原子基态的电子组态及原子态是（）

基态原子的4s能级中只有1个电子的元素共有（）

A salvor may be（）the whole or part of the payment due under Salvage Convention to the extent that the salvage operations have become necessary or more difficult because of fault or neglect on his part or if the salvor has been guilty of fraud or other dishonest conduct.

A mark or place at which a vessel comes under obligatory entry，transit，or escort procedure is know as（）.