Palladium (Pd)
Palladium is element 46, a transition metal in group 10, period 5. A neutral atom has 46 protons, 60 neutrons and 46 electrons, 18 of them valence electrons.
Transition metal- Atomic number
- 46
- Atomic mass
- 106.42 u
- Valence electrons
- 18*
- Protons · neutrons
- 46 · 60
- Electrons per shell
- 2, 8, 18, 18
- At room temperature
- solid
Bohr model of palladium
The Bohr model draws palladium as a nucleus of 46 protons and 60 neutrons, with its 46 electrons on 4 circular shells: 2 in shell 1, 8 in shell 2, 18 in shell 3, 18 in shell 4. Press Build the atom to watch the shells fill from the inside out. The outer ring (the N 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 palladium
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 4d¹⁰
Short form (noble gas notation): [Kr] 4d¹⁰. The [Kr] stands for the electrons of krypton, the noble gas before it.
Palladium breaks the usual filling order. The Aufbau rule predicts 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d⁸, but experiments show the configuration above. The energy levels of the subshells are so close here that a different arrangement wins.
How many valence electrons does palladium have?
Palladium has 18 valence electrons.
Palladium is a transition metal, so its valence electrons are less clear-cut than for main-group elements. It has 18 electrons in its outermost shell (shell 4), and electrons in its inner d subshell can also take part in bonding.
Protons, neutrons and electrons
| Protons | 46 | equal to the atomic number |
|---|---|---|
| Electrons | 46 | equal to the protons in a neutral atom |
| Neutrons | 60 | mass number 106 − 46 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.
Palladium properties
| Symbol | Pd |
|---|---|
| Category | Transition metal |
| Group · period · block | 10 · 5 · d |
| Atomic mass | 106.42 u |
| State at 25 °C | solid |
| Melting point | 1,828 K (1,550 °C, 2,830 °F) |
| Boiling point | 3,236 K (2,960 °C, 5,370 °F) |
| Density | 12 g/cm³ |
| Electronegativity (Pauling) | 2.2 |
| Atomic radius | 202 pm |
| First ionization energy | 8.337 eV |
| Electron affinity | 0.557 eV |
| Oxidation states | +3, +2 |
| Common ion charge | +3, +2 |
| Discovered | 1803 by William Hyde Wollaston |
Where palladium sits on the periodic table
Group 10: Nickel, Platinum, Darmstadtium.
Questions about palladium
How many valence electrons does palladium have?
Palladium has 18 valence electrons in its outer shell; inner d or f electrons can also bond.
How many protons, neutrons and electrons does palladium have?
A neutral palladium atom has 46 protons and 46 electrons. Its most common form has about 60 neutrons (mass number 106 − 46 protons).
What is the electron configuration of palladium?
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 4d¹⁰, written in short form as [Kr] 4d¹⁰.
What does the Bohr model of palladium look like?
A nucleus of 46 protons and 60 neutrons, circled by 4 electron shells holding 2, 8, 18, 18 electrons.
What is the atomic number of palladium?
46. The atomic number is the number of protons in the nucleus, and it is what makes an atom palladium.