CHEM 101 Lecture Notes - Lecture 2: Atomic Number, Chemical Property, Physical Property
Document Summary
Isotopes- atoms of the same element (with the same atomic number) that have different mass. The atomic mass of an element is given as the average mass of the isotopes. The number of electrons is equal to the number of protons in a neutral atoms. During chemical changes atoms gain or lose electrons and become ions. Physical property- tells about characteristics and appearance (use your senses) Chemical property- tells whether a substance is transformed into a new substance. Chemical change or chemical reaction- transformation of one or more atoms or molecules into one or more different molecules. Liquid-definite volume, but they take on whatever shape of the container it occupies. Gasses- have neither a definite shape or a definite volume and they must be contained on all sides, taking on the shape and volume of the container. Representative elements- most important elements represented in living things.
