إربيوم (Eu): Bohr Model, Protons, Neutrons & Electrons
إربيوم is element number 63, a lanthanide in the f-block (the lanthanide row drawn below the table), period 6. Its atom has 63 protons, 90 neutrons and 63 electrons arranged in 6 shells: 2, 8, 18, 25, 8, 2.
Protons, neutrons and electrons in europium
ال atomic number of europium is 63, so every europium atom has 63 protons. A neutral atom has the same number of electrons, 63. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For europium-153, that is 153 − 63 = 90 neutrons. Europium has 2 stable isotopes, with 88, 90 neutrons.
How to draw the Bohr model of europium
- Draw the nucleus and write 63 p⁺ تم تصميم [الخدمة] لمتعلمين من جميع الأعمار، بما في ذلك طلاب المدارس. 90 n⁰ inside it.
- Draw the first shell and put 2 electrons on it (the first shell holds at most 2).
- Draw the second shell and put 8 electrons on it.
- Draw the third shell and put 18 electrons on it.
- Draw the fourth shell and put 25 electrons on it.
- Draw the fifth shell and put 8 electrons on it.
- Draw the sixth shell and put 2 electrons on it.
- Check: 2 + 8 + 18 + 25 + 8 + 2 = 63 electrons, the same as the number of protons.
From potassium onwards the shells don’t simply fill as 2, 8, 8: the fourth shell starts before the third is full, so the real arrangement above (2, 8, 18, 25, 8, 2) is the one to draw.
Electron configuration
The electron configuration of europium is [Xe] 6s² 4f⁷. As a lanthanide it fills an inner f-subshell, and its common ion is Eu³⁺.
Key facts about europium
| Symbol | Eu |
|---|---|
| Atomic number | 63 |
| Relative atomic mass | 151.96 |
| Group · period · block | f-block · period 6 |
| نوع | لانثانيد |
| State at 25 °C | solid |
| أغلفة الإلكترون | 2, 8, 18, 25, 8, 2 |
| Electron configuration | [Xe] 6s² 4f⁷ |
| Valence electrons | varies (outer shell: 2) |
| Common ion | Eu³⁺ |
| Electronegativity (Pauling) | 1.20 |
| First ionisation energy | 5.67 eV (547 kJ/mol) |
| Atomic radius (empirical) | 185 pm |
Where europium sits on the periodic table
الأسئلة الشائعة
How many protons, neutrons and electrons does europium have?
Europium has 63 protons and 63 electrons (atomic number 63). Its most common isotope, europium-153, has 153 − 63 = 90 neutrons.
What is the electron configuration of europium?
[Xe] 6s² 4f⁷. In shells that is 2, 8, 18, 25, 8, 2.
How many valence electrons does europium have?
Europium is a lanthanide, so its valence electrons are spread over two shells; its outermost shell holds 2.
Where is europium on the periodic table?
In the f-block (the lanthanide row drawn below the table), period 6, in the f-block. It is a lanthanide.
