Back Periode 4 element Afrikaans Elementos d'o periodo 4 AN आवर्त 4 तत्व ANP عناصر الدورة الرابعة Arabic Elementos del periodu 4 AST Dövri sistemin dördüncü periodu Azerbaijani पीरियड 4 तत्व Bihari চতুর্থ পর্যায়ের মৌল Bengali/Bangla Elements del període 4 Catalan 4. perioda Czech
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A period 4 element is one of the chemical elements in the fourth row (or period) of the periodic table of the chemical elements. The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when chemical behaviour begins to repeat, meaning that elements with similar behaviour fall into the same vertical columns. The fourth period contains 18 elements beginning with potassium and ending with krypton – one element for each of the eighteen groups. It sees the first appearance of d-block (which includes transition metals) in the table.