Koi

Koi,  ₂₀Ca

ngoi-kôn
dull gray, silver; with a pale yellow tint Spectral lines of calcium
Kî-pún sin-sit
Miàng, fù-ho	Koi, Ca
Yîn-ngî	calcium
ngoi-hìn	dull gray, silver; with a pale yellow tint
Koi chhai chû-khì-péu ke vi-chi
Mg ↑ Ca ↓ Sr Kap ← Koi → scandium
ngièn-chṳ́ sì-sú	20
ngièn-chṳ́-liòng (±)	40.078(4)
ngièn-su lui-phe̍t	kán-thú kîm-su̍k
Chhu̍k, fûn-khî	2 chhu̍k, s-block
chû-khì	period 4
thien-chṳ́ phài-lie̍t	[Ar] 4s2
per shell	2, 8, 8, 2
vu̍t-lî sin-chṳt
Siông	ku-thí
yùng-tiám	1115 K ​(842 °C, ​1548 °F)
pui-tiám	1757 K ​(1484 °C, ​2703 °F)
Me̍t-thu near Sit-vûn	1.55 g·cm−3
1.378 g·cm−3
Yùng-fa-ngie̍t	8.54 kJ·mol−1
Chîn-fat-ngie̍t	154.7 kJ·mol−1
Ngie̍t-yùng-liong	25.929 J·mol−1·K−1
chîn-hi-ap P (Pa) 1 10 100 1 k 10 k 100 k chhai T (K) 864 956 1071 1227 1443 1755
Ngièn-chṳ́ sin-chṳt
Yông-fa-su	+2, +1, −1 ​(a strongly basic oxide)
Thien-fu-sin	Pauling scale: 1.00
Thien-lì-nèn	1st: 589.8 kJ·mol−1 2nd: 1145.4 kJ·mol−1 3rd: 4912.4 kJ·mol−1 (more)
Ngièn-chṳ́ pan-kang	empirical: 197 pm
Khiung-ka pan-kang	176±10 pm
Van der Waals pan-kang	231 pm
Miscellanea
Chîn-thí keu-chho	​face-centered cubic (fcc)
Sâng-suk thin rod	3810 m·s−1 (at 20 °C)
Ngie̍t-phàng-chong	22.3 µm·m−1·K−1 (at 25 °C)
Ngie̍t-chhòn-thô-li̍t	201 W·m−1·K−1
Thien-chú-li̍t	33.6 nΩ·m (at 20 °C)
Chhṳ̀-sin	diamagnetic
Young's modulus	20 GPa
Shear modulus	7.4 GPa
Bulk modulus	17 GPa
Poisson ratio	0.31
Mohs hardness	1.75
Brinell hardness	170–416 MPa
CAS Registry Number	7440-70-2
Le̍k-sú
Hoat-kiàn kap siōng chá ê tông-ūi-sò͘	Humphry Davy (1808)
Chui vún-thin ke thùng-vi-su
Chú vùn-chông: Koi ke thùng-vi-su
iso NA half-life DM DE (MeV) DP 40Ca 96.941% >5.9×1021 y (β+β+) 0.194 40Ar 41Ca trace 1.03×105 y ε – 41K 42Ca 0.647% 42Ca is stable with 22 neutrons 43Ca 0.135% 43Ca is stable with 23 neutrons 44Ca 2.086% 44Ca is stable with 24 neutrons 45Ca syn 162.7 d β− 0.258 45Sc 46Ca 0.004% >8.8×1022 y (β−β−) 0.988 46Ti 47Ca syn 4.536 d β− 0.694, 1.99 47Sc γ 1.297 – 48Ca 0.187% 4.3×1019 y β−β− 4.274 48Ti (β−) 0.0058 48Sc
Decay modes in parentheses are predicted, but have not yet been observed

Koi (鈣) he yit-chúng fa-ho̍k ngièn-su, fa-ho̍k fù-ho vì Ca, ngièn-chṳ́ su-muk he 20, chhai Ngièn-su chû-khì-péu chûng thi-ngi-sṳ̍p vi.