Flag of the Element Erbium

Flag of the Element Holmium

Flag for the Element of Dysprosium

Flag for the Element of Terbium

Flag for the Element of Gadolinium

Flag for the Element of Europium

It just a coincidence that the scientific flag for Europium uses the main colours of the EU flag on its field: dark blue and yellow.  Blue, or indI go is Coded to 6 while yellow is Coded to 3, which is reflective of Europium's Z number.  

Flag for the Element of Samarium

Flag for the Element of Promethium

Flag for the Element of Neodymium

Flag for the Element of Praseodymium

Flag for the Element of Cerium

Flag for the Element of Lantanum

Flag for the Element of Barium

Flag for the Element of Cesium

Flag for the Element of Xenon

Flag for the Element of Iodine

Flag for the Element Tellurium

Flag for the Element of Antimony

Flag for the Element of Tin

Flag for the Element Indium

Flag of the Element Cadmium

Flag of the Element Silver

Flag of the Element Palladium

Flag of the Element Rhodium

Flag of the Element Ruthenium

Flag of the Element Technetium

Flag of the Element Molybdenum

Flag of the Element of Niobium

Flag of the Element Zirconium

Flag of the Element Yttrium

Flag of the Element Strontium

Flag of Rubidium

Flag for the Element of Krypton

Flag for the Element of Bromine

Flag of the Element of Arsenic & Selenium

Arsenic is the 33rd element, in the third period so it gets a full center of yellow since yellow is associated with 3.  The red and blue stripes along the top and bottom reflect the numbers 15, and this is the group this element belongs to. The blue central disc with symbol for Arsenic is reflective of the letter P flag, as this element is on the P-Block

Selenium is the 34th element so it gets a yellow and green field reflective of the numbers 3 and 4 for 34. 

Flag for the Element of Germanium

Flag for the Element of Gallium

Flag for the Element of Zinc

Flag for the Element of Copper

Flag for the Element of Nickel

Flag for the Element of Cobalt

Flag for the Element of Iron

Flag for the Element of Manganese

Flag for the Element of Chromium

Flag for the Element of Vanadium

Flag for the Element of Titanium

Flag for the Element of Scandium

Flag for the Element of Calcium

Flag for the Element of Potassium