Put two elements side by side. Use position, properties and real-world uses to reason about similarities and differences.
Element A H — Hydrogen He — Helium Li — Lithium Be — Beryllium B — Boron C — Carbon N — Nitrogen O — Oxygen F — Fluorine Ne — Neon Na — Sodium Mg — Magnesium Al — Aluminium Si — Silicon P — Phosphorus S — Sulfur Cl — Chlorine Ar — Argon K — Potassium Ca — Calcium Sc — Scandium Ti — Titanium V — Vanadium Cr — Chromium Mn — Manganese Fe — Iron Co — Cobalt Ni — Nickel Cu — Copper Zn — Zinc Ga — Gallium Ge — Germanium As — Arsenic Se — Selenium Br — Bromine Kr — Krypton Rb — Rubidium Sr — Strontium Y — Yttrium Zr — Zirconium Nb — Niobium Mo — Molybdenum Tc — Technetium Ru — Ruthenium Rh — Rhodium Pd — Palladium Ag — Silver Cd — Cadmium In — Indium Sn — Tin Sb — Antimony Te — Tellurium I — Iodine Xe — Xenon Cs — Caesium Ba — Barium La — Lanthanum Ce — Cerium Pr — Praseodymium Nd — Neodymium Pm — Promethium Sm — Samarium Eu — Europium Gd — Gadolinium Tb — Terbium Dy — Dysprosium Ho — Holmium Er — Erbium Tm — Thulium Yb — Ytterbium Lu — Lutetium Hf — Hafnium Ta — Tantalum W — Tungsten Re — Rhenium Os — Osmium Ir — Iridium Pt — Platinum Au — Gold Hg — Mercury Tl — Thallium Pb — Lead Bi — Bismuth Po — Polonium At — Astatine Rn — Radon Fr — Francium Ra — Radium Ac — Actinium Th — Thorium Pa — Protactinium U — Uranium Np — Neptunium Pu — Plutonium Am — Americium Cm — Curium Bk — Berkelium Cf — Californium Es — Einsteinium Fm — Fermium Md — Mendelevium No — Nobelium Lr — Lawrencium Rf — Rutherfordium Db — Dubnium Sg — Seaborgium Bh — Bohrium Hs — Hassium Mt — Meitnerium Ds — Darmstadtium Rg — Roentgenium Cn — Copernicium Nh — Nihonium Fl — Flerovium Mc — Moscovium Lv — Livermorium Ts — Tennessine Og — Oganesson ⇄ Element B H — Hydrogen He — Helium Li — Lithium Be — Beryllium B — Boron C — Carbon N — Nitrogen O — Oxygen F — Fluorine Ne — Neon Na — Sodium Mg — Magnesium Al — Aluminium Si — Silicon P — Phosphorus S — Sulfur Cl — Chlorine Ar — Argon K — Potassium Ca — Calcium Sc — Scandium Ti — Titanium V — Vanadium Cr — Chromium Mn — Manganese Fe — Iron Co — Cobalt Ni — Nickel Cu — Copper Zn — Zinc Ga — Gallium Ge — Germanium As — Arsenic Se — Selenium Br — Bromine Kr — Krypton Rb — Rubidium Sr — Strontium Y — Yttrium Zr — Zirconium Nb — Niobium Mo — Molybdenum Tc — Technetium Ru — Ruthenium Rh — Rhodium Pd — Palladium Ag — Silver Cd — Cadmium In — Indium Sn — Tin Sb — Antimony Te — Tellurium I — Iodine Xe — Xenon Cs — Caesium Ba — Barium La — Lanthanum Ce — Cerium Pr — Praseodymium Nd — Neodymium Pm — Promethium Sm — Samarium Eu — Europium Gd — Gadolinium Tb — Terbium Dy — Dysprosium Ho — Holmium Er — Erbium Tm — Thulium Yb — Ytterbium Lu — Lutetium Hf — Hafnium Ta — Tantalum W — Tungsten Re — Rhenium Os — Osmium Ir — Iridium Pt — Platinum Au — Gold Hg — Mercury Tl — Thallium Pb — Lead Bi — Bismuth Po — Polonium At — Astatine Rn — Radon Fr — Francium Ra — Radium Ac — Actinium Th — Thorium Pa — Protactinium U — Uranium Np — Neptunium Pu — Plutonium Am — Americium Cm — Curium Bk — Berkelium Cf — Californium Es — Einsteinium Fm — Fermium Md — Mendelevium No — Nobelium Lr — Lawrencium Rf — Rutherfordium Db — Dubnium Sg — Seaborgium Bh — Bohrium Hs — Hassium Mt — Meitnerium Ds — Darmstadtium Rg — Roentgenium Cn — Copernicium Nh — Nihonium Fl — Flerovium Mc — Moscovium Lv — Livermorium Ts — Tennessine Og — Oganesson
Atomic number 8 26
Atomic mass 15.999 55.845
Group 16 8
Period 2 4
Block P D
Category Nonmetal Transition metal
Phase Gas Solid
Electron structure [He] 2s2 2p4 [Ar] 3d6 4s2
O has the lower atomic number; Fe comes later in the periodic table. They sit in different periods and groups, so first locate each, then apply the trend arrows. 