Question

valence electrons
noble - gas configurations are useful because they help differentiate the number of valence electrons in an atom. valence electrons determine many of an atoms physical and chemical properties.
electron - dot structures are simple diagrams that show the number of valence electrons, represented as dots around the element symbol. elements in the same group have the same number of electron dots because they have the same number of valence electrons. for example, carbon and silicon both have four dots in their electron - dot structures.
noble gas configurations and electron dot structures for period 3 elements
group 1 2 13 14 15 16 17 18
element na mg al si p s cl ar
noble gas configuration ne3s¹ ne3s² ne3s²3p¹ ne3s²3p² ne3s²3p³ ne3s²3p⁴ ne3s²3p⁵ ne3s²3p⁶
number of valence electrons 1 2 3 4 5 6 7 8
electron - dot structure na· ·mg· ·al· ·si· ·p· :s· :cl· :ar:
the number of dots around an elements symbol indicates the number of valence electrons. for example, silicon has 4 electrons.
adding the superscripts in the noble gas configuration gives the number of valence electrons. for example, argon has 8 valence electrons (2 + 6 = 8).
32 ccc patterns recall that elements above and below each other in the periodic table have similar physical and chemical properties. what do you think might account for these similar properties? explain.

Explanation:

Elements in the same group of the periodic table have the same number of valence electrons. Valence electrons determine an atom's physical and chemical properties. Since elements above and below each other have the same valence - electron count, they exhibit similar properties.

Answer:

Elements above and below each other in the periodic table have similar physical and chemical properties because they have the same number of valence electrons, which largely determine these properties.