Presentation on theme: "Atoms, Elements, and the Periodic Table. PART 1: ATOMS 1.What are atoms made of? NUCLEUS – center of the atom PROTON (+) (in nucleus) NEUTRON (0) (in."— Presentation transcript:
How many protons and electrons are there in an atom? The number of PROTONS & ELECTRONS in an atom are ALWAYS EQUAL.
How are electrons described in an atom? ELECTRONS form a cloud because we dont know exactly where they are at any given moment.
What takes up the most space in a atom? Most of the atom is taken up by the space between the nucleus and the electrons.
What subatomic particle is the heaviest? Lightest to heaviest: electron<proton = neutron
What is an element? An ELEMENT = any substance that cannot be broken down into simpler substances. An element is made of only 1 kind of atom. Every atom of an element has the same number of protons.
Who was the first person to organize the elements? Dmitri Mendeleev was the first person to organize the elements. He made the first periodic table. He organized it in order of increasing atomic mass. How are the elements arranged today? The elements in todays Periodic Table are arranged by their atomic number.
What is an atomic number? ATOMIC NUMBER = the number of protons in an atom. This tells you what kind of element it is. (at the top of the box) What is a mass number? MASS NUMBER = The sum of the protons and neutrons in an atom. (not on the periodic table)
What is a chemical symbol? CHEMICAL SYMBOL = a short way of telling what the chemical is. Its usually 1 or 2 letters. EXAMPLES: Barium = Ba Tungsten = W
What is atomic mass? ATOMIC MASS = the average mass of an element. This includes all the isotopes of that element. mass ++ 3 321
What is a period on the periodic table? A PERIOD = a horizontal row in the periodic table. There are 7 of them. Elements in a period change from left to right according to a pattern. There is a trend that the elements follow.
What is a group on the periodic table? A GROUP = A vertical column on the periodic table. Also called a FAMILY. There are 18 of them. Elements in a group all have similar characteristics. Groups are often named for the top element in the column. EXAMPLE: Carbon group Nitrogen family