BIOA01H3 Chapter 2: chapter 2
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BIOA01H3 Full Course Notes
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Chapter 2. 1 what are the chemical elements that make up living organisms? y atoms: all matter is composed of them and they are tiny. y nucleus: each atom consists of a dense, positively charged. One or more negatively charged electrons move around the nucleus. The number of protons in the nucleus of an atom determines its element. y neutrons: one of the three most fundamental particles of matter, with mass approximately. In text, immediately preceding the symbol for an element, the atomic number is written at the lower left and the mass number at the upper left. First shell: the innermost electron shell consists of just one orbital, called an s orbital. Second shell: the second shell contains four orbitals (an s orbital and three p orbitals). Additional shells: elements with more than ten electrons have three or more electron shells. A single bond involves the sharing of a single pair of electrons.
