click below
click below
Normal Size Small Size show me how
Science Chapter 4
Elements and the Periodic Table
Question | Answer |
---|---|
atom | the smallest particle of an element |
electrons | the negatively charged particles of an atom |
nucleus | a tiny region in the center of an atom |
protons | the positively charged particles in the nucleus of an atom |
neutrons | the electrically neutral particle of an atom |
atomic number | the unique number of protons in the nucleus of an atom that helps identify the element |
isotopes | atoms with the same number of protons and a difference number of neutrons |
mass number | the sum of the protons and neutrons in the nucleus of an atom, helps identify isotopes |
Mendeleev | Russian scientist that discovered a set of patterns that applied to all the elements |
First Periodic Table | arranged in order of increasing atomic mass |
atomic mass | the average mass of all the isotopes of an element |
periods | horizontal rows on the Period Table |
groups | the 18 vertical columns, consist of elements with similar characteristics |
chemical symbol | one or two letter abbreviation of an element's name |
physical properties of metal | ductility, conductivity, malleability, shininess |
reactivity | the ease and speed with which elements combine and react with other elements and compounds |
nonmetals | elements that lack most of the properties of a metal |
metalloids | has some characteristics of metals and some of nonmetals |
semiconductors | substances that can conduct electricity under some conditions but not under others |