All practice pages/Interatomic theory/Elements
Element 96, an actinide
Named for Marie and Pierre Curie, and used to read the chemistry of rocks on Mars.
Period 7, in the actinide row set below the main table. The other actinides are tinted, and every cell opens its own article.
Curium has 96 electrons, one for every proton, so the atom carries no charge. Below are the same 96 electrons written two ways.
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d¹⁰ 5f⁷ 6s² 6p⁶ 6d¹ 7s²
Short form: [Rn] 5f⁷ 6d¹ 7s², where [Rn] stands for the 86 electrons radon already has.
That list runs by shell. In the order the subshells fill it reads [Rn] 7s² 5f⁷ 6d¹, because a subshell fills by its energy, not by its shell number.
The simple form counts electrons shell by shell. The orbital form says which subshell each one sits in: s holds 2, p holds 6, d holds 10 and f holds 14. Shell 4 here is 4s² 4p⁶ 4d¹⁰ 4f¹⁴, and 2 + 6 + 10 + 14 is 32.
Curium sits in period 7 and has 7 shells. The period number counts the shells.
The outer shell holds 2 electrons. Those are the ones curium can lose, gain or share, so they are the ones that decide what it bonds with.
Radioactive, like every actinide. It gives up electrons to form positive ions.
Not found in nature. It forms in nuclear reactors from plutonium and americium.
Glenn Seaborg, Ralph James and Albert Ghiorso made it in 1944 in Chicago by bombarding plutonium-239 with alpha particles, a few months before americium. It was named after Marie and Pierre Curie, just as gadolinium above it honors Johan Gadolin.
Curium-244 is the radiation source in the X-ray spectrometers that Mars rovers from Sojourner to Curiosity used to identify the elements in rocks. It is also used to make heavier elements for research.
Intensely radioactive, and stored in bone and the liver if taken into the body.