问题
填空题
1999年俄、美科学家联合小组合成了第114号元素的一种同位素，该核素原子的质量数为298，则这种同位素原子的核内中子数为______，核内质子数为______．
答案
第114号元素的一种同位素，其质子数为114，
质量数为298，则中子数为298-114=184，
故答案为：184；114．
搜题请搜索小程序“爱下问搜题”
1999年俄、美科学家联合小组合成了第114号元素的一种同位素，该核素原子的质量数为298，则这种同位素原子的核内中子数为______，核内质子数为______．
第114号元素的一种同位素，其质子数为114，
质量数为298，则中子数为298-114=184，
故答案为：184；114．
| The "Karat" marking on jewelry tells you what proportion of gold is mixed with other metals, ff 14 parts of gold are mixed with 10 parts of base metal, the combination is called 14-Karat (14K) gold. The higher the Karat rating, the higher the proportion of gold in the object. The lowest Karat gold that can be marketed in the United States is 10-Karat gold. Jewelry does not have to be marked with its Karat quality, but most of it is. ff there is a Karat quality mark, next to it must be the U.S. registered trademark of the person or company that will stand behind the mark, as required by the National Gold and Silver Stamping Act. |
If gold is marked with a Karat quality mark, it must also
A．bear a national gold and silver stamp.
B．bear the registered trademark of the entity standing behind the mark.
C．bear a "made in the USA" mark.
D．bear a percentage mark.