Chemistry Unit 2 Vocab

Front

Atomic Mass

Back

weighted average of the element’s isotope

Front

Alpha Particles

Back

a helium-4 nucleus ( 42 𝐻𝑒 or 42α) with a charge of +2 that consists of

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Cathode

Back

the negative battery electrode that receives electrons in an electrical circuit; in an electrochemical cell, reduction takes place at the cathode terminal

Front

Cathode Ray

Back

emitted from the negative electrode in a gas discharge tube; these negative particles are called electrons and β-particle

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Isotope

Back

atoms of the same element with different atomic masses due to different amounts of neutrons

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Law

Back

provides a description of a directly observable phenomenon; describes what will or is expected to happen in a certain set of circumstances

Front

Law of Definite Proportions

Back

whenever two or more elements combine to form a compound, they do so in a definite proportion by mass

Front

Subatomic particles

Back

protons (positively charged) and neutrons (neutral) in the nucleus, and electrons (negatively charged) surrounding the nucleus

Front

Theory

Back

a set of statements or principles to explain a group of facts or phenomena and are repeatedly tested and widely accepted; explain why something happens, but not how

Front

Absorption spectrum

Back

when electrons of an element in the ground state absorb energy in order to reach a higher energy state. The frequencies of light transmitted through this substance, with dark bands showing absorbed light, constitute the absorption spectrum of the substance