الرصاص (Pb): Bohr Model, Protons, Neutrons & Electrons
الرصاص is element number 82, a post-transition metal in group 14, period 6. Its atom has 82 protons, 126 neutrons and 82 electrons arranged in 6 shells: 2, 8, 18, 32, 18, 4.
Protons, neutrons and electrons in lead
ال atomic number of lead is 82, so every lead atom has 82 protons. A neutral atom has the same number of electrons, 82. The number of neutrons depends on the isotope: neutrons = mass number − atomic number. For lead-208, that is 208 − 82 = 126 neutrons. Lead has 4 stable isotopes, with 122, 124, 125, 126 neutrons.
How to draw the Bohr model of lead
- Draw the nucleus and write 82 p⁺ تم تصميم [الخدمة] لمتعلمين من جميع الأعمار، بما في ذلك طلاب المدارس. 126 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 18 electrons on it.
- Draw the sixth shell and put 4 electrons on it.
- Check: 2 + 8 + 18 + 32 + 18 + 4 = 82 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, 18, 4) is the one to draw.
Electron configuration
The electron configuration of lead is [Xe] 6s² 4f¹⁴ 5d¹⁰ 6p². Its 4 outer electrons decide how it reacts: it tends to lose them, forming Pb²⁺ ions.
Key facts about lead
| Symbol | Pb |
|---|---|
| Atomic number | 82 |
| Relative atomic mass | 207.2 |
| Group · period · block | group 14 · period 6 · p-block |
| نوع | Post-transition Metal |
| State at 25 °C | solid |
| أغلفة الإلكترون | 2, 8, 18, 32, 18, 4 |
| Electron configuration | [Xe] 6s² 4f¹⁴ 5d¹⁰ 6p² |
| Valence electrons | 4 |
| Common ion | Pb²⁺ |
| Electronegativity (Pauling) | 2.33 |
| First ionisation energy | 7.42 eV (716 kJ/mol) |
| Atomic radius (empirical) | 180 pm |
Where lead sits on the periodic table
الأسئلة الشائعة
How many protons, neutrons and electrons does lead have?
Lead has 82 protons and 82 electrons (atomic number 82). Its most common isotope, lead-208, has 208 − 82 = 126 neutrons.
What is the electron configuration of lead?
[Xe] 6s² 4f¹⁴ 5d¹⁰ 6p². In shells that is 2, 8, 18, 32, 18, 4.
How many valence electrons does lead have?
4. Lead is in group 14, and its outer shell holds 4 electrons.
Where is lead on the periodic table?
In group 14, period 6, in the p-block. It is a post-transition metal.
