Physical properties of the halogens · 卤素的物理性质
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| halogen/ˈhælədʒn/ | 卤素 | lǔ sù |
| diatomic/ˌdaɪəˈtɒmɪk/ | 双原子 | shuāng yuán zi |
| volatility/ˌvɒləˈtɪlɪti/ | 挥发性 | huī fā xìng |
| bond energy/bɒnd ˈenədʒi/ | 键能 | jiàn néng |
| reactivity/rɪəkˈtɪvɪti/ | 反应活性 | fǎn yìng huó xìng |
Meet the salt-formers
- The halogens 卤素 are the Group 17 elements; they exist as diatomic 双原子 molecules ($\text{Cl}_2$, $\text{Br}_2$, $\text{I}_2$).
- They change colour and state going down the group.
- Their volatility 挥发性 falls down the group.
认识盐的形成者
- 卤素(halogens)是第 17 族元素;它们以双原子(diatomic)分子存在($\text{Cl}_2$、$\text{Br}_2$、$\text{I}_2$)。
- 它们沿族向下改变颜色和状态。
- 它们的挥发性(volatility)沿族向下下降。
Halogen physical trend lab · 卤素物理趋势实验室
Follow halogens down the group and link state, colour and volatility. · 沿族向下跟踪卤素,并联系状态、颜色和挥发性。
The halogens exist as diatomic molecules. · 卤素以双原子分子存在。
They form X₂ molecules: Cl₂, Br₂, I₂. · 它们形成 X₂ 分子:Cl₂、Br₂、I₂。
The halogens become less reactive down Group 17. · 卤素沿第 17 族向下变得不那么活泼。
The outer shell is further from the nucleus, so gaining an electron is harder. · 外壳层离原子核更远,所以得到一个电子更难。
Colour, state and volatility
| Element | At room temperature |
|---|---|
| chlorine | pale green gas |
| bromine | red-brown liquid |
| iodine | grey-black solid |
- Volatility decreases down the group: larger molecules with more electrons have stronger London (dispersion) forces, so boiling points rise.
The halogens change from gas to liquid to solid down the group as volatility falls
颜色、状态和挥发性
| 元素 | 在室温下 |
|---|---|
| 氯 | 淡绿色气体 |
| 溴 | 红棕色液体 |
| 碘 | 灰黑色固体 |
- 挥发性沿族向下减小:有更多电子的更大分子有更强的伦敦(色散)力(London/dispersion forces),所以沸点上升。
卤素沿族向下从气体变到液体变到固体,因为挥发性下降
At room temperature, the states of chlorine, bromine and iodine are: · 在室温下,氯、溴和碘的状态是:
Chlorine is a gas, bromine a liquid and iodine a solid — volatility falls down the group. · 氯是气体,溴是液体,碘是固体——挥发性沿族向下下降。
Volatility decreases down Group 17 because: · 挥发性沿第 17 族向下减小,因为:
More electrons give stronger instantaneous/induced dipole (London) forces, raising the boiling point. · 更多电子给出更强的瞬时/诱导偶极(伦敦)力,提高沸点。
Match each halogen to its state at room temperature. · 把每个卤素匹配到它在室温下的状态。
Each item links the term to its correct meaning. · 每一项把术语链接到它正确的含义。
Bond energy 键能
- The $\text{X}\text{–}\text{X}$ bond energy generally falls from $\text{Cl}_2$ to $\text{I}_2$.
- The shared electrons are further from the nuclei in the larger atoms.
Bromine is a Group 17 halogen: a dark liquid giving an orange vapour
键能
- $\text{X}\text{–}\text{X}$ 键能总体上从 $\text{Cl}_2$ 到 $\text{I}_2$ 下降。
- 在更大的原子中共享电子离原子核更远。
溴是一种第 17 族卤素:一种给出橙色蒸气的暗色液体
The X–X bond energy generally falls from Cl₂ to I₂ because: · X–X 键能从 Cl₂ 到 I₂ 总体下降,因为:
In bigger atoms the bonding electrons are further from the nuclei, so the bond is weaker. · 在更大的原子中成键电子离原子核更远,所以键更弱。
The trend in reactivity 反应活性
- Halogen reactivity decreases down the group: the larger atom attracts an extra electron less strongly.
- This is why chlorine displaces bromine and iodine, but not the other way round.
反应性的趋势
- 卤素反应性沿族向下减小:更大的原子吸引一个额外电子不那么强烈。
- 这就是为什么氯置换溴和碘,但反过来不行。
You've got it
- halogens are diatomic Group 17 elements: Cl₂ (green gas), Br₂ (red-brown liquid), I₂ (grey-black solid)
- volatility decreases down (more electrons → stronger London forces → higher boiling point)
- the X–X bond energy falls down the group
你掌握了
- 卤素是双原子第 17 族元素:Cl₂(绿色气体)、Br₂(红棕色液体)、I₂(灰黑色固体)
- 挥发性沿族向下减小(更多电子 → 更强的伦敦力 → 更高的沸点)
- X–X 键能沿族向下下降