19 K Potassium 39.098 u

Potassium

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周期
4
族
1
区块
s-区块
相态 (STP)
Solid

Potassium is an essential alkali metal for all living cells. It is the seventh most abundant element in Earth's crust.

外观: 银白色金属

About Potassium

Essential to every living cell, potassium is a soft, silvery alkali metal that reacts vigorously with water. It has atomic number 19 and an atomic mass of 39.098, a notably large atomic radius of 243 pm, and a low melting point of 337 K. Its single valence electron ([Ar] 4s1) is loosely held, giving the low electronegativity of 0.82 and a first ionization energy of just 419 kJ/mol. Humphry Davy first isolated the metal in 1807. Potassium is the seventh most abundant element in Earth's crust, but its reactivity means it never occurs free. It belongs to group 1, period 4.

物理属性

原子质量 39.098 u
密度 0.862 g/cm³
熔点 63.6 °C
沸点 758.9 °C
STP相态 Solid
原子半径 243.0 pm

电子属性

电负性 0.82
电离能 418.8 eV
电子亲和能 48.4 eV
价电子 1

电子构型

构型 [Ar] 4s¹

Electron Shell Configuration

Potassium electron shell configuration K 2e⁻ 8e⁻ 8e⁻ 1e⁻
Electron shell structure of Potassium — electrons per shell.
Shell Electrons
1 (K) 2
2 (L) 8
3 (M) 8
4 (N) 1

Position in Periodic Table

Potassium position in the periodic table K

发现

发现者: Humphry Davy
年份: 1807

区块与周期

区块

s p d f

周期

1 2 3 4 5 6 7

元素周期表

镧系元素 锕系元素

含K的反应

Lead Iodide Precipitation (Golden Rain)

Pb(NO₃)₂ + 2KI → PbI₂↓ + 2KNO₃

Precipitation

Potassium Reacting with Water

2K + 2H₂O → 2KOH + H₂

Single Replacement

Chlorine Displacing Iodine from Potassium Iodide

Cl₂ + 2KI → 2KCl + I₂

Single Replacement

Lead Nitrate and Potassium Iodide (Golden Rain)

Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃

Double Replacement

Thermal Decomposition of Potassium Chlorate

2KClO₃ → 2KCl + 3O₂

Decomposition
查看全部13个反应 →

Compounds Containing Potassium

Potassium Hydroxide

KOH

Potassium Nitrate

KNO₃

Potassium Chloride

KCl

Potassium Permanganate

KMnO₄

Potassium Dichromate

K₂Cr₂O₇

Potassium Iodide

KI

Potassium Carbonate

K₂CO₃

Potassium Phosphate Dibasic

K₂HPO₄

Potassium Aluminum Sulfate

KAl(SO₄)₂

Potassium Ferricyanide

K₃[Fe(CN)₆]

Potassium Ferrocyanide

K₄[Fe(CN)₆]

Potassium Persulfate

K₂S₂O₈

更多碱金属

3 Li Lithium 11 Na Sodium 37 Rb Rubidium 55 Cs Cesium 87 Fr Francium

Frequently Asked Questions

What is Potassium?
Potassium (K) is a chemical element with atomic number 19. It is a solid at standard temperature and pressure, classified as a 碱金属.
What are the key properties of Potassium?
Potassium has an atomic mass of 39.098 u, density of 0.862 g/cm³, melting point of 63.6°C, boiling point of 758.9°C.
What is the electron configuration of Potassium?
The electron configuration of Potassium is [Ar] 4s1. It is in the s-block of the periodic table.
Who discovered Potassium?
Potassium was discovered by Humphry Davy in 1807.
What is the electronegativity of Potassium?
Potassium has an electronegativity of 0.82 on the Pauling scale.