Nobelium (لا): Bohr Model, Protons, Neutrons & Electrons
Nobelium is element number 102, an actinide in the f-block (the actinide row drawn below the table), period 7. Its atom has 102 protons, 157 neutrons and 102 electrons arranged in 7 shells: 2, 8, 18, 32, 32, 8, 2.
Protons, neutrons and electrons in nobelium
ال atomic number of nobelium is 102, so every nobelium atom has 102 protons. A neutral atom has the same number of electrons, 102. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For nobelium-259, that is 259 − 102 = 157 neutrons. Every isotope of nobelium is radioactive; 259 is the mass number of its most stable one.
How to draw the Bohr model of nobelium
- Draw the nucleus and write 102 p⁺ تم تصميم [الخدمة] لمتعلمين من جميع الأعمار، بما في ذلك طلاب المدارس. 157 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 32 electrons on it.
- Draw the fifth shell and put 32 electrons on it.
- Draw the sixth shell and put 8 electrons on it.
- Draw the seventh shell and put 2 electrons on it.
- Check: 2 + 8 + 18 + 32 + 32 + 8 + 2 = 102 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, 32, 32, 8, 2) is the one to draw.
Electron configuration
The electron configuration of nobelium is [Rn] 7s² 5f¹⁴. As an actinide it fills an inner f-subshell, and its common ion is variable.
Key facts about nobelium
| Symbol | لا |
|---|---|
| Atomic number | 102 |
| Relative atomic mass | [259] |
| Group · period · block | f-block · period 7 |
| نوع | الأكتينيد |
| State at 25 °C | unknown |
| أغلفة الإلكترون | 2, 8, 18, 32, 32, 8, 2 |
| Electron configuration | [Rn] 7s² 5f¹⁴ |
| Valence electrons | varies (outer shell: 2) |
| Common ion | — |
| Electronegativity (Pauling) | 1.30 |
| First ionisation energy | 6.65 eV (642 kJ/mol) |
| Atomic radius (empirical) | — |
Where nobelium sits on the periodic table
الأسئلة الشائعة
How many protons, neutrons and electrons does nobelium have?
Nobelium has 102 protons and 102 electrons (atomic number 102). Its most common isotope, nobelium-259, has 259 − 102 = 157 neutrons.
What is the electron configuration of nobelium?
[Rn] 7s² 5f¹⁴. In shells that is 2, 8, 18, 32, 32, 8, 2.
How many valence electrons does nobelium have?
Nobelium is an actinide, so its valence electrons are spread over two shells; its outermost shell holds 2.
Where is nobelium on the periodic table?
In the f-block (the actinide row drawn below the table), period 7, in the f-block. It is an actinide.
