Platinum (Pt)

Platinum properties

Atomic number

78

Atomic mass

195.08 u

Category

Transition metal

Group

10

Period

6

Block

d-block

State at room temp.

Solid

Electronegativity

2.28

Melting point

2,041.4 K (1,768.2 °C)

Boiling point

4,098 K (3,824.8 °C)

Density

21.45 g/cm³

Valence electrons

1

Common charges

+2, +4

Oxidation states

+4, +2

Atomic radius

209 pm

Ionization energy

9 eV

Electron affinity

2.128 eV

Radioactive

No, has stable isotopes

Discovered

1735

Platinum electron configuration

The electron configuration of Platinum (Pt) is [Xe] 4f14 5d9 6s1. Its 78 electrons are arranged in shells as 2, 8, 18, 32, 17, 1.

Protons, neutrons and electrons in Platinum

A neutral Platinum atom has 78 protons and 78 electrons. Most Platinum atoms have about 117 neutrons: the atomic mass rounded to 195, minus the atomic number 78.

Neutrons are approximate: atoms of the same element can have different numbers of neutrons (isotopes). Atomic number and mass

How many valence electrons does Platinum have?

1

Platinum has 1 valence electron, counting the electrons in its outermost s subshell. Like most transition metals, it can also use d electrons in bonding.

See every element: Periodic table with valence electrons

Platinum orbital diagram

Each box is an orbital that holds up to two electrons with opposite spins (↑↓). The inner shells are the same as the noble gas in brackets. How to write electron configurations

Molar mass of Platinum

195.08 g/mol

One mole of Platinum atoms (6.022 × 10²³ atoms) has a mass of 195.08 grams. Use this value to convert between grams and moles.

Compounds containing Platinum

Platinum facts

• The international prototype kilogram, which defined the kilogram from 1889 until 2019, is made of 90 percent platinum and 10 percent iridium.
• Spanish colonists called it platina, 'little silver', and at first treated it as an unwanted impurity in gold.
• Platinum (Pt) has atomic number 78 and is a solid at room temperature. It was discovered in 1735.

Position in the periodic table

Platinum is element 78, in period 6 and group 10 of the periodic table, in the d-block.

All transition metals

Uses of Platinum

Platinum is used in catalytic converters, especially in diesel vehicles, and in jewelry. Industry uses platinum catalysts to make nitric acid for fertilizers, refine petroleum, and power hydrogen fuel cells. Platinum is also found in laboratory equipment, temperature sensors, and pacemaker electrodes, and the platinum-containing drug cisplatin is widely used in cancer chemotherapy.

Who discovered Platinum?

Platinum was used by Indigenous peoples of South America long before Europeans knew of it. Spanish naval officer Antonio de Ulloa encountered it in 1735 during an expedition to South America, and his description, published in 1748, introduced it to European science.

Where does the name come from?

Platinum comes from the Spanish platina, meaning 'little silver', a diminutive of plata, 'silver'. Spanish colonists in South America used the name for the silvery grains of metal they found mixed with gold.

Discovery timeline