1.简单
氯化钠(食盐)靠哪种键结合在一起?
- A共价键
- B氢键
- C金属键
- D离子键
2.简单
Elements in the same period of the periodic table have the same number of what?
- AProtons
- BValence electrons
- COccupied electron shells
- DNeutrons
3.简单
现代元素周期表中,元素是如何排列的?
- A按中子数递增
- B按原子序数递增
- C按发现的日期
- D按元素符号的字母顺序
4.中等
A plastic block has a density of 0.8 g/cm³. What happens when it is placed in water (density 1.0 g/cm³)?
- AIt floats
- BIt dissolves
- CIt sinks
- DIt stays suspended halfway down
5.中等
How is 0.00045 written in scientific notation?
- A4.5 × 10⁴
- B4.5 × 10⁻⁵
- C4.5 × 10⁻³
- D4.5 × 10⁻⁴
6.中等
How does dissolving salt in water affect the water's boiling point?
- AIt lowers the boiling point slightly
- BIt makes the water boil at room temperature
- CIt raises the boiling point slightly
- DIt has no effect on the boiling point
7.困难
Which substance has the lowest boiling point?
- AHelium
- BSodium chloride
- CIron
- DWater
8.困难
对于这样小的分子来说,水的沸点为什么异常地高?
- A它是离子化合物
- B它的分子非常重
- C必须破坏其分子之间强的氢键
- D沸腾时它的 O–H 键断裂
答案
- 1. D · 离子键
- 2. C · Occupied electron shells
- 3. B · 按原子序数递增
- 4. A · It floats
- 5. D · 4.5 × 10⁻⁴
- 6. C · It raises the boiling point slightly
- 7. A · Helium
- 8. C · 必须破坏其分子之间强的氢键
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