He
Helium is the second lightest and second most abundant element in the observable universe.
Physical Properties
| পদাৰ্থ | 4.0026 u |
| ঘনত্ব | 0.0001785 g/cm³ |
| Melting Point | 0.95 K |
| উত্তাপৰ বিন্দু | 4.22 K |
| আকৃতি | Colorless gas |
| State at Room Temp | Gas |
রাসায়নিক বৈশিষ্ট্যসমূহ
| 1- তম আইনাইজেশন শক্তি | 2372.3 kJ/mol |
| ইলেকট্ৰন | -48.0 kJ/mol |
| Oxidation States | 0 |
প্ৰমাণপত্ৰৰ বৈশিষ্ট্য
| ইলেকট্ৰন | 1s2 |
| পৰমাণু | 31.0 pm |
| কোভালেন্ট বেৰিয়াড | 28.0 pm |
| Van der Waals Radius | 140.0 pm |
ডিস্কভাৰী
| আবিষ্কাৰ কৰা হৈছে | Pierre Janssen, Joseph Norman Lockyer |
| আবিষ্কাৰৰ বছৰ | 1868 |
| অৱস্থান | Guntur, India / London, England |
| Named After | Greek 'helios' meaning sun |
বিষয়ে Helium
Helium is a colorless, odorless, inert monatomic gas that heads the noble gas series. It has the lowest boiling point of all elements at 4.22 K and can only be solidified under pressure. Helium is formed on Earth through radioactive alpha decay of heavy elements. It was first detected spectroscopically in the Sun before being found on Earth.
Uses & Applications
Cryogenics, MRI machines, party balloons, deep-sea diving gas mixtures, leak detection, and semiconductor manufacturing.
মজা কথা
Helium is the only element that was discovered in space before it was found on Earth, first observed in the solar spectrum during a solar eclipse in 1868.
আইসোটোপ
| Mass Number | অভাৱ | হাফ-লাইফ | Stable |
| 3 | 0.00000134% | - | Yes |
| 4 | 0.99999866% | - | Yes |
ইলেকট্ৰন
1s2