Tantalum (Ta)
Tantalum is element 73, a transition metal in group 5, period 6. A neutral atom has 73 protons, 108 neutrons and 73 electrons, 2 of them valence electrons.
Transition metal- Atomic number
- 73
- Atomic mass
- 180.95 u
- Valence electrons
- 2*
- Protons · neutrons
- 73 · 108
- Electrons per shell
- 2, 8, 18, 32, 11, 2
- At room temperature
- solid
Bohr model of tantalum
The Bohr model draws tantalum as a nucleus of 73 protons and 108 neutrons, with its 73 electrons on 6 circular shells: 2 in shell 1, 8 in shell 2, 18 in shell 3, 32 in shell 4, 11 in shell 5, 2 in shell 6. Press Build the atom to watch the shells fill from the inside out. The outer ring (the P 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 tantalum
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d³
Short form (noble gas notation): [Xe] 6s² 4f¹⁴ 5d³. The [Xe] stands for the electrons of xenon, the noble gas before it.
How many valence electrons does tantalum have?
Tantalum has 2 valence electrons.
Tantalum is a transition metal, so its valence electrons are less clear-cut than for main-group elements. It has 2 electrons in its outermost shell (shell 6), and electrons in its inner d subshell can also take part in bonding.
Protons, neutrons and electrons
| Protons | 73 | equal to the atomic number |
|---|---|---|
| Electrons | 73 | equal to the protons in a neutral atom |
| Neutrons | 108 | mass number 181 − 73 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.
Tantalum properties
| Symbol | Ta |
|---|---|
| Category | Transition metal |
| Group · period · block | 5 · 6 · d |
| Atomic mass | 180.95 u |
| State at 25 °C | solid |
| Melting point | 3,290 K (3,020 °C, 5,460 °F) |
| Boiling point | 5,731 K (5,460 °C, 9,860 °F) |
| Density | 16.4 g/cm³ |
| Electronegativity (Pauling) | 1.5 |
| Atomic radius | 217 pm |
| First ionization energy | 7.89 eV |
| Electron affinity | 0.322 eV |
| Oxidation states | +5 |
| Common ion charge | +5 |
| Discovered | 1802 by Anders Gustaf Ekeberg |
Where tantalum sits on the periodic table
Group 5: Vanadium, Niobium, Dubnium.
Questions about tantalum
How many valence electrons does tantalum have?
Tantalum has 2 valence electrons in its outer shell; inner d or f electrons can also bond.
How many protons, neutrons and electrons does tantalum have?
A neutral tantalum atom has 73 protons and 73 electrons. Its most common form has about 108 neutrons (mass number 181 − 73 protons).
What is the electron configuration of tantalum?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d³, written in short form as [Xe] 6s² 4f¹⁴ 5d³.
What does the Bohr model of tantalum look like?
A nucleus of 73 protons and 108 neutrons, circled by 6 electron shells holding 2, 8, 18, 32, 11, 2 electrons.
What is the atomic number of tantalum?
73. The atomic number is the number of protons in the nucleus, and it is what makes an atom tantalum.