Across
- 4. a set of postulates defining atoms as the fundamental, indivisible particles of matter that combine in simple, fixed ratios to form chemical compounds
- 6. the dense, positively charged central core of an atom that contains protons and neutrons
- 7. the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.
- 8. a chart that organizes all known chemical elements in order of increasing atomic number, displaying them in rows (periods) and columns (groups) to show recurring patterns in their properties
- 9. a stable, negatively charged subatomic particle with negligible mass that orbits the positively charged nucleus of an atom in shells or orbitals
- 11. The smallest part of a substance that cannot be broken down chemically
- 13. a subatomic particle located in the nucleus of an atom that has no electric charge and a mass slightly greater than a proton
- 14. a vertical column of elements on the periodic table
Down
- 1. the total count of protons and neutrons in its nucleus, which represents the atom's approximate mass
- 2. the negatively charged electrode by which electrons enter an electrical device.
- 3. a unit of mass used to express atomic and molecular weights, equal to one-twelfth of the mass of an atom of carbon-12.
- 5. the mass of an atom of a chemical element expressed in atomic mass units
- 8. a horizontal row in the periodic table, where each row corresponds to a specific number of electron shells or energy levels an atom of an element occupies
- 10. a variant of a chemical element that has the same number of protons but a different number of neutrons in its atomic nucleus
- 12. a positively charged subatomic particle found in the nucleus of every atom