Zumdahl Chemistry Chapter 4a Objectives and Key Terms Chemical Foundations: Elements and Atoms In this chapter, your goals are to: 1. Learn about the relative abundances of the elements 2. Learn the names of some elements 3. Learn the symbols of some elements 4. Learn about Dalton’s theory of atoms 5. Understand and illustrate the law of constant composition 6. Learn how a formula describes a compound’s composition 7. Learn about the internal parts of an atom 8. Understand Rutherford’s experiment to characterize the atom’s structure 9. Understand some important features of subatomic particles 10. Learn about the terms isotope, atomic number, and mass number 11. Understand the use of the symbol ZA X to describe a given atom. 12. Learn the nature of nuclear radiation, including alpha ,beta, and gamma Radiation. 13. Predict the product of a particular type of radiation. Alpha Particle a type of nuclear radiation, characterized by a particle containing 2 protons and 2 Neutrons, also called a helium nucleus. Atom The fundamental unit of which elements are composed. Atomic number The number of protons in the nucleus of an atom; each element has a unique atomic number. Beta radiation a type of nuclear radiation, composed of an electron “from the nucleus” Chemical formula A representation of a molecule in which the symbols for the elements are used to indicate the types of atoms present and subscripts are used to show the relative numbers of atoms. Diatomic molecule A molecule composed of two atoms. Electron A negatively charged particle that occupies the space around the nucleus of an atom. Gamma radiation a type of nuclear radiation, comprised of a high energy photon Ionic compound A compound that results when a metal reacts with a nonmetal to form cations and anions. Isotopes Atoms of the same element (the same number of protons) that have different numbers of neutrons. They have identical atomic numbers but different mass numbers. Law of constant composition A given compound always contains elements in exactly the same proportion by mass. Mass number The total number of protons and neutrons in the atomic nucleus of an atom. Neutron A particle in the atomic nucleus with a mass approximately equal to that of the proton but with no charge. Nuclear atom The modern concept of the atom as having a dense center of positive charge (the nucleus) and electrons moving around the outside. Nucleus The small, dense center of positive charge in an atom. Periodic table A chart showing all the elements arranged in columns in such a way that all the elements in a given column exhibit similar chemical properties. Proton A positively charged particle in an atomic nucleus.