Periodic Trends · 周期趋势
| English | 中文 | Pinyin · 拼音 |
|---|---|---|
| atomic radius/əˈtɒmɪk ˈreɪdɪəs/ | 原子半径 | yuán zi bàn jìng |
| ionization energy/ˌaɪənaɪˈzeɪʃn ˈenədʒi/ | 电离能 | diàn lí néng |
| electronegativity/ɪˌlektrəʊŋɡəˈtɪvɪti/ | 电负性 | diàn fù xìng |
Patterns on the table
- Line up the elements and their properties rise and fall in waves.
- Size shrinks left to right, then jumps at the next row.
- The energy to steal an electron climbs across, drops down.
- One idea -- the tug of the nucleus -- explains it all.
周期表上的规律
- 把元素排好队,它们的性质就像波浪一样起起落落。
- 尺寸从左到右缩小,到下一行又跳大。
- 夺走一个电子所需的能量横向上升、纵向下降。
- 一个思想——核的拉力——就能解释这一切。
Atomic radius
- Atomic radius 原子半径 shrinks across a period and grows down a group.
- Across: more protons pull the same shell in tighter.
- Down: each new shell sits farther out.
原子半径
- 原子半径横穿一个周期时缩小,沿一族向下时增大。
- 横向:质子更多,把同一电子层拉得更紧。
- 纵向:每个新电子层都坐得更靠外。
Across a period from left to right, the atomic radius... · 在同一周期从左到右，原子半径……
More protons pull the same shell in tighter, shrinking the atom. · 更多的质子将同一壳层拉得更紧，使原子收缩。
Order these period-3 atoms from LARGEST to SMALLEST radius. · 将这些第 3 周期的原子按半径从大到小排序。
Radius shrinks across a period, so Na > Si > Cl. · 半径在同一周期内缩小，所以 Na > Si > Cl。
Ionization energy
- Ionization energy 电离能 is the energy to remove an electron.
- It rises across a period (stronger pull) and falls down a group (farther out).
- This is the opposite trend to atomic radius.
电离能
- 电离能是移走一个电子所需的能量。
- 它横穿周期时上升(拉力更强),沿族向下时下降(离得更远)。
- 这与原子半径的趋势相反。
Ionization energy and atomic radius follow opposite trends. · 电离能与原子半径呈相反趋势。
A smaller, tightly-held atom takes more energy to ionize. · 体积小且束缚紧密的原子需要更多能量才能电离。
Going down a group, ionization energy generally... · 沿族向下，电离能通常……
Outer electrons are farther out and shielded, so easier to remove. · 外层电子距离更远且受到屏蔽，因此更容易移除。
Electronegativity
- Electronegativity 电负性 is an atom's pull on the shared electrons in a bond.
- It is highest at the top right (ignoring noble gases) and lowest at the bottom left.
- Fluorine is the most electronegative element.
电负性
- 电负性是原子对键中共享电子的拉力。
- 它在右上角最高(不算稀有气体),在左下角最低。
- 氟是电负性最强的元素。
Across a period · 同一周期内
Step across Period 3 and watch atomic radius, ionisation energy and melting point change. · 横跨第 3 周期，观察原子半径、电离能和熔点的变化。
Which element is the most electronegative? · 哪种元素的电负性最强？
Fluorine (top right, not a noble gas) has the strongest pull on shared electrons. · 氟（右上角，非稀有气体）对共用电子的吸引力最强。
Which is smaller, sodium (Na) or chlorine (Cl)?
- Both sit in period 3, but Cl has more protons.
- The stronger pull shrinks Cl, so chlorine is smaller.
钠(Na)和氯(Cl)哪个更小?
- 两者都在第三周期,但 Cl 有更多质子。
- 更强的拉力使 Cl 缩小,所以氯更小。
Down a group, inner electrons ____ the outer ones from the full nuclear charge. · 沿族向下，内层电子____外层电子免受完整核电荷的影响。
Inner electrons shield (screen) the outer ones, weakening the effective pull. · 内层电子屏蔽（筛除）外层电子，削弱了有效吸引力。
Two competing factors drive the trends: more protons pull harder (across a period), while extra shells push electrons out and shield them (down a group). Ionization energy and atomic radius run in opposite directions. And "across" does not always beat "down" -- compare two elements carefully rather than guessing.
两个相互竞争的因素驱动这些趋势:质子更多则拉力更强(横穿周期),而额外的电子层把电子推向外并屏蔽它们(沿族向下)。电离能与原子半径方向相反。而且"横向"并不总是胜过"纵向"——要仔细比较两个元素,而不是靠猜。
Across a period the nucleus pulls harder, so atomic radius shrinks while ionization energy and electronegativity rise. Down a group new shells add distance and shielding, so radius grows while ionization energy and electronegativity fall. Radius runs opposite to the other two.
横穿一个周期,核拉得更紧,所以原子半径缩小,而电离能和电负性上升。沿一族向下,新电子层增加了距离和屏蔽,所以半径增大,而电离能和电负性下降。半径与另外两者方向相反。