Interpreting the Periodic Table H He LiBeBCNOFNe NaMg KCa AlSiPSClAr
ATOMIC NUMBER The number of protons in an atom 19 K 39.1 atomic number
MASS NUMBER (atomic mass) The number of protons AND neutrons in an atom 19 K 39.1 atomic mass
Rules of Atomic Structure: 1.Atomic number = number of protons 2. Mass number = number of protons + number of neutrons How do we determine the number of neutrons in an element? 3. Number of neutrons = mass number (rounded to the nearest whole number) – atomic number 3. Number of protons = number of electrons in a neutral atom
Atomic Structure -Radius of electron cloud is approximately times larger than the nucleus -An atom is similar to our Solar System electrons are found in distinct orbits around the nucleus -We refer to the orbits as orbital shells
p + n nucleus (protons + neutrons) 1 st shell (max. 2 electrons) 2 nd shell (max. 8 electrons) 3 rd shell (max. 8 electrons) 4 th shell (max. 2 electrons) Orbital Shells
Valence electron: Electron in the outer shell of an atom that can participate in forming chemical bonds with other atoms
Group 1 elements 1 valence electron Group 2 elements 2 valence electrons Group 13 elements 3 valence electrons Group 14 elements 4 valence electrons Group 15 elements 5 valence electrons Group 16 elements 6 valence electrons Group 17 elements 7 valence electrons Group 18 elements 8 valence electrons Self check:
H He LiBeBCNOFNe NaMg KCa AlSiPSClAr
HYDROGEN (H) PROTONS: 1 NEUTRONS: 0
HELIUM (He) PROTONS: 2 NEUTRONS: 2
LITHIUM (Li) PROTONS: 3 NEUTRONS: 4
BERYLLIUM (Be) PROTONS: 4 NEUTRONS: 5
BORON (B) PROTONS: 5 NEUTRONS: 6
CARBON (C) PROTONS: 6 NEUTRONS: 6
NITROGEN (N) PROTONS: 7 NEUTRONS: 7
OXYGEN (O) PROTONS: 8 NEUTRONS: 8
FLUORINE (F) PROTONS: 9 NEUTRONS: 10
NEON (Ne) PROTONS: 10 NEUTRONS: 10
SODIUM (Na) PROTONS: 11 NEUTRONS: 12
MAGNESIUM (Mg) PROTONS: 12 NEUTRONS: 12
ALUMINUM (Al) PROTONS: 13 NEUTRONS: 14
SILICON (Si) PROTONS: 14 NEUTRONS: 14
PHOSPHORUS (P) PROTONS: 15 NEUTRONS: 16
SULFUR (S) PROTONS: 16 NEUTRONS: 16
CHLORINE (Cl) PROTONS: 17 NEUTRONS: 18
ARGON (Ar) PROTONS: 18 NEUTRONS: 22
POTASSIUM (K) PROTONS: 19 NEUTRONS: 20
CALCIUM (Ca) PROTONS: 20 NEUTRONS: 20