The Periodic Table And how to find the

The Periodic Table …And how to find the number of protons, neutrons & electrons in ANY atom!

ASAP Science Element Song § https: //www. youtube. com/watch? v=Vg. VQKCcfwn. U

The Periodic Table Elements are organized based on their physical and chemical properties in the periodic table: § Elements listed in rows by increasing atomic number § Rows are called periods § Columns are called families or groups § Elements with similar properties line up in vertical columns

Periods Families or groups

Dmitri Mendeleev § Godfather of the periodic table § 1 st guy smart enough to record important properties of known metals and find a way to organize it § Also considered elements that had not been discovered yet.

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The Periodic Table Copy this into your notes so that you know what the numbers mean when you look at the periodic table.

The Periodic Table § Atomic number: number of protons in the nucleus of each atom of an element (always a whole #) § Atomic mass: mass of an average atom of an element; measured in atomic mass unit (amu) and written as a decimal § Mass number: a count of the number of particles in an atom’s nucleus Mass number = (number of protons) + (number of neutrons)

How to find the number of protons, electrons and neutrons 1. The number of protons is… § # of protons = ATOMIC NUMBER 2. The number of electrons is… § Atoms have a neutral charge so they must have an equal number of protons and electrons § THEREFORE… Atomic number = # of protons = # of electrons

3. The number of neutrons is… § Mass number = (number of protons) + (number of neutrons) § Mass number is not given in the periodic table BUT. . . all you need to do is round the atomic mass to the nearest whole number

SUMMARY: How to find p, e, n for any element! # protons = atomic number of element # electrons = # protons (or rounded off atomic mass) # neutrons = mass number – # protons

Ex. Find the # of protons, electrons and neutrons for the following elements. § Atomic number is 36 § # of protons = 36 § # of electrons = 36 § Atomic mass = 83. 80 § Mass number = 84 § Mass number = (# of protons) + (# of neutrons) 84 = 36 + (# of neutrons) § # of neutrons = 84 – 36 = 48

Element Atomic # Atomic mass Sn 50 118. 7 119 Cu 29 63. 5 64 He 2 4 4 Mass number Number of of of protons electron neutrons s 50 50 119 -50= 69 29 29 64 -29 = 35 2 2 4 -2 = 2

Charges Listed on the Periodic Table § Ion charge: an electric charge that forms when an atom gains or loses electrons § This is listed in the Periodic Table § Ion: a charged atom § If an atom loses electron(s) positive charge (lost negative charge) § If an atom gains electron(s) negative charge (gains negative charge)