Chem

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boron

boron

Atomic number 5, symbol B. A metalloid element with 3 valence electrons. Used in alloys, fertilizers, and as a neutron absorber.

neutron

Particle found in the nucleus of an atom, with no electrical charge and a mass of approximately 1 atomic mass unit.

atom

Flashcard: A fundamental unit of matter, consisting of a nucleus (protons and neutrons) surrounded by electrons. It is the building block of all chemical elements./a

helium

Element with atomic number 2 and symbol He. It is a colorless, odorless, and non-toxic gas. It has low density and is the second lightest element. Helium is commonly used in balloons, as a coolant in certain scientific applications, and as a protective gas in welding.