Physical properties across Period 3 · 第三周期的物理性质
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| periodicity/ˌpɪərɪˌɒˈdɪsɪti/ | 周期性 | zhōu qī xìng |
| atomic radius/əˈtɒmɪk ˈreɪdɪəs/ | 原子半径 | yuán zi bàn jìng |
| nuclear charge/ˈnjuːklɪə tʃɑːdʒ/ | 核电荷 | hé diàn hè |
| melting point/ˈmeltɪŋ pɔɪnt/ | 熔点 | róng diǎn |
| giant covalent/ˈdʒaɪənt ˈkəʊvələnt/ | 巨型共价 | jù xíng gòng jià |
| simple molecular/ˈsɪmpl məˈlekjʊlə/ | 分子晶体 | fēn zǐ jīng tǐ |
A trip across Period 3
- Periodicity 周期性 means properties repeat in a regular pattern across each period.
- Period 3 (Na to Ar) is the standard example.
- The trends follow from the structure and bonding.
横穿第三周期的一次旅行
- 周期性(periodicity)意味着性质在每个周期横向以一个规则的模式重复。
- 第三周期(Na 到 Ar)是标准的例子。
- 这些趋势源于结构和键合。
Periodicity means that properties: · 周期性意味着性质:
Periodicity is the repeating pattern of properties across the periods of the table. · 周期性是性质横穿表的周期的重复模式。
Across Period 3, atomic radius decreases. · 横穿第三周期,原子半径减小。
Increasing nuclear charge pulls electrons closer. · 增加的核电荷把电子拉得更近。
Atomic radius 原子半径
- Across Period 3 the atomic radius gets smaller.
- The nuclear charge 核电荷 rises but the electrons go into the same outer shell, so the stronger pull draws it in.
Atomic radius decreases across Period 3
原子半径
- 横穿第三周期原子半径变小。
- 核电荷(nuclear charge)上升,但电子进入同一个外壳层,所以更强的拉力把它拉进来。
原子半径横穿第三周期减小
Across Period 3, the atomic radius: · 横穿第三周期,原子半径:
More protons pull the outer shell in more strongly, while shielding stays about the same. · 更多质子更强地把外壳层拉进来,而屏蔽保持大致相同。
Melting point 熔点 and conductivity
- Na, Mg, Al are giant metallic — melting points rise, and they conduct well.
- Si is giant covalent 巨型共价 — the highest melting point; it barely conducts.
- P, S, Cl, Ar are simple molecular 分子晶体 — low melting points (weak forces); they don't conduct.
熔点和电导率
- Na、Mg、Al 是巨型金属——熔点上升,它们导电好。
- Si 是巨型共价——最高的熔点;它几乎不导电。
- P、S、Cl、Ar 是简单分子——低熔点(弱的力);它们不导电。
Melting point across Period 3 · 横穿第三周期的熔点
Melting point peaks at giant-covalent silicon, then collapses at the simple-molecular and atomic non-metals. Step across to see the giant-to-simple switch. · 熔点在巨型共价的硅达到峰值,然后在简单分子和原子的非金属处崩溃。横向走一遍,看巨型到简单的转变。
Which element has the highest melting point in Period 3? · 第三周期中哪个元素有最高的熔点?
Silicon's giant covalent network needs strong covalent bonds broken, giving the highest melting point. · 硅的巨型共价网络需要断裂强的共价键,给出最高的熔点。
Which Period 3 elements conduct electricity well? · 哪些第三周期元素导电好?
The metals Na, Mg, Al conduct well; from silicon onwards conductivity is almost zero. · 金属 Na、Mg、Al 导电好;从硅起电导率几乎为零。
Match each Period 3 fact to the right item. · 把每个第三周期事实匹配到正确的项。
Each item links the term to its correct meaning. · 每一项把术语链接到它正确的含义。
The giant-to-simple switch
- Across Period 3 the structure changes from giant metallic → giant covalent (silicon) → simple molecular.
- Melting point peaks at silicon, then drops sharply.
巨型到简单的转变
- 横穿第三周期,结构从巨型金属 → 巨型共价(硅)→ 简单分子改变。
- 熔点在硅达到峰值,然后急剧下降。
You've got it
- periodicity = properties repeat across each period
- atomic radius decreases across (more nuclear charge, same shell)
- melting point peaks at silicon (giant covalent); high for metals, low for molecular
- Na/Mg/Al conduct (metallic); from Si onwards they barely conduct
你掌握了
- 周期性 = 性质横穿每个周期重复
- 原子半径减小横穿(更多核电荷,同一壳层)
- 熔点在硅达到峰值(巨型共价);金属高,分子低
- Na/Mg/Al 导电(金属);从 Si 起它们几乎不导电