ELEMENTS AND THE PERIODIC TABLE CHAPTER 15 ELEMENTS AND THE PERIODIC TABLE

ORGANIZING ELEMENTS Dmitri Mendeleev Looked at similar physical and chemical properties Atomic mass: the average mass of one atom of the element Bonding power: the number of chemical bonds an element can form

FIRST PERIODIC TABLE Mendeleev noticed patterns when elements were arranged in order of increasing atomic mass Periodic table, the properties of the elements repeat in each row

ATOM INSIDE OUTSIDE NUCLEUS: THE CORE OF THE ATOM PROTONS: POSITIVE CHARGE NEUTRONS: NEUTRAL CHARGE OUTSIDE ELECTRON CLOUD OR ELECTRON ORBIT ELECTRONS: NEGATIVE CHARGE

ATOM ATOMIC MASS UNIT: USED TO MEASURE THE PARTICLES OF AN ATOM AMU ATOMIC NUMBER: THE NUMBER OF PROTONS IN THE NUCLEUS UNIQUE FOR EACH ELEMENT AN ATOM HAS A NEUTRAL CHARGE

READING THE PERIODIC TABLE AN ELEMENT’S PROPERTIES CAN BE PREDICTED FROM ITS LOCATION IN THE PERIODIC TABLE GROUPS: THE VERTICAL COLUMNS 18 ALSO KNOWN AS FAMILIES PERIODS: THE HORIZONTAL ROWS 7 PERIODS

Fe INSIDE THE SQUARE IRON 26 55.847 ATOMIC NUMBER ELEMENT SYMBOL ELEMENT NAME 55.847 ATOMIC MASS

VALENCE ELECTRONS THE ELECTRONS THAT ARE INVOLVED IN TRANSFER OR SHARING IN THE CHEMICAL BONDS THE ELEMENTS IN EACH GROUP OF THE PERIODIC TABLE HAVE THE SAME NUMBER AND ARRANGEMENT OF VALENCE ELECTRONS

8 5 1 3 6 2 7 4 2 – 3- 4- 5 2 - 3