Calcium

potassiumcalciumscandium
Mg

Ca

Sr
Appearance
dull gray, silver


Spectral lines of calcium
General properties
Name, symbol, numbercalcium, Ca, 20
Pronunciationm/ KAL-see-əm
Element categoryalkaline earth metal
Group, period, block2, 4, s
Standard atomic weight40.078(4) g/mol
Electron configuration[Ar] 4s2
Electrons per shell2, 8, 8, 2 (Image)
Physical properties
Phasesolid
Density (near r.t.)1.55 g/cm3
Liquid density at m.p.1.378 g/cm3
Melting point1115 K, 842 °C, 1548 °F
Boiling point1757 K, 1484 °C, 2703 °F
Heat of fusion8.54 kJ/mol
Heat of vaporization154.7 kJ/mol
Specific heat capacity(25 °C) 25.929 J/(mol·K)
Vapor pressure
P (Pa)1101001 k10 k100 k
at T (K)8649561071122714431755
Atomic properties
Oxidation states+2, +1[1]
(strongly basic oxide)
Electronegativity1.00 (Pauling scale)
Ionization energies
1st: 589.8 kJ/mol
2nd: 1145.4 kJ/mol
3rd: 4912.4 kJ/mol
Atomic radius197 pm
Covalent radius176±10 pm
Van der Waals radius231 pm
Miscellanea
Crystal structureface-centered cubic
Magnetic orderingdiamagnetic
Electrical resistivity(20 °C) 33.6 nΩ·m
Thermal conductivity(300 K) 201 W/(m·K)
Thermal expansion(25 °C) 22.3 µm/(m·K)
Speed of sound (thin rod)(20 °C) 3810 m/s
Young's modulus20 GPa
Shear modulus7.4 GPa
Bulk modulus17 GPa
Poisson ratio0.31
Mohs hardness1.75
Brinell hardness167 MPa
CAS registry number7440-70-2
Most stable isotopes
Main article: Isotopes of calcium
isoNAhalf-lifeDMDE (MeV)DP
40Ca96.941%>5.9×1021 y0.19440Ar
41Catrace1.03×105 yε-41K
42Ca0.647%42Ca is stable with 22 neutrons
43Ca0.135%43Ca is stable with 23 neutrons
44Ca2.086%44Ca is stable with 24 neutrons
45Casyn162.7 dβ0.25845Sc
46Ca0.004%>2.8×1015 y0.98846Ti
47Casyn4.536 dβ0.694, 1.9947Sc
γ1.297-
48Ca0.187%4.3×1019 y4.27448Ti
β
(not observed)
0.005848Sc
Very pure calcium metal, not corroded
Calcium metal in air, corroded

Calcium is a chemical element. Its symbol on the periodic table (a list of all the elements) is Ca. Its atomic number is 20. (The atomic number says where Calcium sits in the periodic table.) It has 20 protons and 20 electrons (if is an atom, see ion). The most common isotopes are Ca-40 and Ca-44. Its mass number is about 40.08. Calcium is very important in the human body, for making bones and for other purposes.

Properties

Physical properties

Calcium is a soft white-gray metal. It is a solid and is opaque. It is an alkaline earth metal. Its melting point is hotter than most other reactive metals. It is a little harder than lead. It has two allotropes. It does not conduct electricity as well as copper, but is much lighter in weight.

Chemical properties

Calcium metal burning

It reacts with water to produce hydrogen and calcium hydroxide. It reacts with water very fast when it is powdered. When it is in a chunk, it starts reacting slowly because calcium hydroxide makes a coating that does not dissolve on the calcium. If a little acid is added to calcium hydroxide, it dissolves it, making the calcium react very fast. It burns when powdered to make a reddish flame. This makes calcium oxide. It also makes calcium nitride when heated. It can react with halogens to make calcium halides like calcium chloride with chlorine.

Calcium compounds

Calcium forms chemical compounds in the +2 oxidation state. Calcium compounds are colorless. Most calcium compounds are not toxic. They are needed in the human body, actually. They are unreactive as far as calcium ions go. Calcium oxide was used to make limelights, which have a flame heating calcium oxide and makes it glow very bright.

Other Languages
Afrikaans: Kalsium
አማርኛ: ካልሲየም
العربية: كالسيوم
aragonés: Calcio
armãneashti: Calciu
asturianu: Calciu
Avañe'ẽ: Itakairã
azərbaycanca: Kalsium
تۆرکجه: کلسیوم
Bân-lâm-gú: Khā-lú-siúm
башҡортса: Кальций
беларуская: Кальцый
беларуская (тарашкевіца)‎: Вапень
भोजपुरी: कैल्सियम
български: Калций
Boarisch: Calcium
བོད་ཡིག: དཀར་ཤམ།
bosanski: Kalcij
brezhoneg: Kalsiom
català: Calci
Чӑвашла: Кальци
Cebuano: Kalsiyum
čeština: Vápník
corsu: Calciu
Cymraeg: Calsiwm
dansk: Calcium
Deutsch: Calcium
ދިވެހިބަސް: ކެލްސިއަމް
Diné bizaad: Káálsiiyin
eesti: Kaltsium
Ελληνικά: Ασβέστιο
English: Calcium
español: Calcio
Esperanto: Kalcio
estremeñu: Calciu
euskara: Kaltzio
فارسی: کلسیم
Fiji Hindi: Calcium
føroyskt: Kalsium
français: Calcium
furlan: Calci
Gaeilge: Cailciam
Gaelg: Kelkium
Gàidhlig: Calcium
galego: Calcio
贛語:
Gĩkũyũ: Calcium
ગુજરાતી: કેલ્શિયમ
客家語/Hak-kâ-ngî: Koi
хальмг: Калцион
한국어: 칼슘
Hawaiʻi: Kalipuna
Հայերեն: Կալցիում
हिन्दी: कैल्सियम
hrvatski: Kalcij
Ido: Kalcio
Bahasa Indonesia: Kalsium
interlingua: Calcium
íslenska: Kalsín
עברית: סידן
Basa Jawa: Kalsium
ქართული: კალციუმი
қазақша: Кальций
Kiswahili: Kalisi
коми: Кальций
Kreyòl ayisyen: Kalsyòm
kurdî: Kalsiyûm
Кыргызча: Кальций
кырык мары: Кальций
Latina: Calcium
latviešu: Kalcijs
Lëtzebuergesch: Kalzium
lietuvių: Kalcis
Limburgs: Calcium
Livvinkarjala: Kal’cii
la .lojban.: bogjinme
magyar: Kalcium
македонски: Калциум
മലയാളം: കാൽ‌സ്യം
Māori: Konupūmā
मराठी: कॅल्शियम
Bahasa Melayu: Kalsium
Mìng-dĕ̤ng-ngṳ̄: Gái (gĭng-sṳ̆k)
монгол: Кальци
မြန်မာဘာသာ: ကယ်လဆီယမ်
Nāhuatl: Tenextepoztli
Nederlands: Calcium
नेपाली: क्याल्सियम
नेपाल भाषा: क्याल्सियम
日本語: カルシウム
Nordfriisk: Kaltsium
norsk: Kalsium
norsk nynorsk: Kalsium
occitan: Calci
oʻzbekcha/ўзбекча: Kalsiy
ਪੰਜਾਬੀ: ਕੈਲਸ਼ੀਅਮ
پنجابی: کیلشیم
Piemontèis: Càuss (element)
Plattdüütsch: Calcium
polski: Wapń
português: Cálcio
română: Calciu
Runa Simi: Isku q'illay
русский: Кальций
саха тыла: Калсиум
संस्कृतम्: कैल्शियम्
Scots: Calcium
Seeltersk: Calcium
shqip: Kalciumi
sicilianu: Calciu (mitallu)
slovenčina: Vápnik
slovenščina: Kalcij
Soomaaliga: Kaalshiyaam
کوردی: کەلسیۆم
српски / srpski: Калцијум
srpskohrvatski / српскохрватски: Kalcij
Basa Sunda: Kalsium
suomi: Kalsium
svenska: Kalcium
Tagalog: Kalsiyo
தமிழ்: கல்சியம்
татарча/tatarça: Кальций
తెలుగు: కాల్షియం
тоҷикӣ: Калсий
Türkçe: Kalsiyum
українська: Кальцій
اردو: کیلشیم
ئۇيغۇرچە / Uyghurche: كالتىسىي
vepsän kel’: Kal'cii
Tiếng Việt: Canxi
文言:
Winaray: Calsyo
吴语:
ייִדיש: קאלציום
Yorùbá: Calcium
粵語:
中文:
Kabɩyɛ: Kalɩsɩyɔm