Which of the following statements is true about the periodic table?

Question

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A period in the periodic table is a horizontal row of chemical elements. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than the element to its left.
In chemistry, a group is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table.
Period 2 elements involve the 2s and 2p orbitals. They include the biologically most essential elements besides hydrogen: carbon, nitrogen, and oxygen.
The elements in a group have similar physical or chemical characteristics of the outermost electron shells of their atoms, as most chemical properties are dominated by the orbital location of the outermost electron.
You may use the diagram below as a visual reference for the organization of elements in the periodic table.
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Which of the Following Statements Is True About the Periodic