ATOMS CHEMISTRY Atoms are the basic building components
ATOMS CHEM-IS-TRY
• Atoms are the basic building components of all matter. • Atoms are composed of three types of particles: protons, neutrons, and electrons. • Protons and neutrons reside in the dense, central, positively-charged nucleus of an atom.
• Electrons orbit the nucleus and are located in the region outside the nucleus.
• The mass of a single proton, for example, is approximately 1. 67 x -27 10 e kg. The mass of an electron is -31 approximately 9. 11 x 10 e kg. • Mass of a neutron 1. 674929 x 10 -27 kg
• Protons have a positive charge (+) • Neutrons are neutral with no charge. • Electrons have a negative electric charge (-). • In a neutral atom, the number of protons always equals the number of electrons.
# protons = atomic number • # electrons in a neutral atom = number of protons • # of neutrons = the difference between the mass number and the atomic number • mass number = protons + neutrons
Arrangement of the electrons • The maximum number of electron in the first energy level = 2 electrons • The maximum number of electron in the second energy level = 8 electrons • The maximum number of electron in the third energy level = 18 electrons • The maximum number of electron in the fourth energy level 32 electrons • The maximum number of electron in the fifth energy = 50 electrons • The maximum number of electron in the sixth energy level = 72 electrons • The maximum number of electron in the seventh energy level = 98 electrons
- Slides: 10