Tin (Sn)
Tin is element 50, a post-transition metal in group 14, period 5. A neutral atom has 50 protons, 69 neutrons and 50 electrons, 4 of them valence electrons.
Post-transition metal- Atomic number
- 50
- Atomic mass
- 118.71 u
- Valence electrons
- 4
- Protons · neutrons
- 50 · 69
- Electrons per shell
- 2, 8, 18, 18, 4
- At room temperature
- solid
Bohr model of tin
The Bohr model draws tin as a nucleus of 50 protons and 69 neutrons, with its 50 electrons on 5 circular shells: 2 in shell 1, 8 in shell 2, 18 in shell 3, 18 in shell 4, 4 in shell 5. Press Build the atom to watch the shells fill from the inside out. The outer ring (the O shell) is dashed: the electrons there are the ones that take part in chemistry.
Real electrons don't travel in neat circles. They live in fuzzy orbitals, shown below, but the Bohr picture is the quickest way to count shells and valence electrons.
Electron configuration of tin
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p²
Short form (noble gas notation): [Kr] 5s² 4d¹⁰ 5p². The [Kr] stands for the electrons of krypton, the noble gas before it.
How many valence electrons does tin have?
Tin has 4 valence electrons.
Tin is in group 14, and for groups 13–18 you subtract 10 from the group number: 14 − 10 = 4. It tends to share electrons in covalent bonds.
Protons, neutrons and electrons
| Protons | 50 | equal to the atomic number |
|---|---|---|
| Electrons | 50 | equal to the protons in a neutral atom |
| Neutrons | 69 | mass number 119 − 50 protons |
Atoms of the same element can have different numbers of neutrons (isotopes). The count above uses the rounded atomic mass, the way it's taught in class.
Tin properties
| Symbol | Sn |
|---|---|
| Category | Post-transition metal |
| Group · period · block | 14 · 5 · p |
| Atomic mass | 118.71 u |
| State at 25 °C | solid |
| Melting point | 505.1 K (232 °C, 449 °F) |
| Boiling point | 2,875 K (2,600 °C, 4,720 °F) |
| Density | 7.287 g/cm³ |
| Electronegativity (Pauling) | 1.96 |
| Atomic radius | 217 pm |
| First ionization energy | 7.344 eV |
| Electron affinity | 1.2 eV |
| Oxidation states | +4, +2 |
| Common ion charge | +4, +2 |
| Discovered | Known since ancient times |
Where tin sits on the periodic table
Group 14: Carbon, Silicon, Germanium, Lead, Flerovium.
Questions about tin
How many valence electrons does tin have?
Tin has 4 valence electrons.
How many protons, neutrons and electrons does tin have?
A neutral tin atom has 50 protons and 50 electrons. Its most common form has about 69 neutrons (mass number 119 − 50 protons).
What is the electron configuration of tin?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p², written in short form as [Kr] 5s² 4d¹⁰ 5p².
What does the Bohr model of tin look like?
A nucleus of 50 protons and 69 neutrons, circled by 5 electron shells holding 2, 8, 18, 18, 4 electrons.
What is the atomic number of tin?
50. The atomic number is the number of protons in the nucleus, and it is what makes an atom tin.