Periodic Table

Elements found on the periodic table are arranged by atomic number and show a periodic pattern of physical and chemical properties. Which is an accurate example of one of these periodic patterns when reading the table from left to right and top to bottom?

• The number of valence electrons increases as the atomic number decreases.
• The number of protons in the nucleus decreases as the atomic number increases.
• The number of valence electrons decreases from the end of one period to the beginning of the next.
• The number of protons in the nucleus decreases from the end of one period to the beginning of the next.

In which pair of elements are both metalloids?

• Sn and Sb
• Sb and Te
• Te and I
• I and Xe

Based on its position in the Periodic Table of the Elements, how many valence electrons does phosphorus (atomic number 15) have?

• 3
• 5
• 8
• 15

A sample of matter is classified as an electrical conductor. The sample is most likely

• a nonmetal with tightly bound electrons.
• a nonmetal with free electrons.
• a metal with tightly bound electrons.
• a metal with free electrons.
  

The number of valence electrons in an element affects the reactivity of that element. Which element listed has the fewest valence electrons?

• beryllium (Be)
• sodium (Na)
• oxygen (O)
• neon (Ne)

According to the Periodic Table of the Elements, which set of elements has similar properties?

• H, C, I
• He, H, Al
• He, Ne, Ar
• Na, Ca, Al

The order of the elements in the periodic table is determined by their

• abundance in nature.
• number of protons.
• number of isotopes.
• atomic mass.

Which element has 2 electrons in the outermost energy level?

• cesium (Cs)
• magnesium (Mg)
• boron (B)
• argon (Ar)

An atom of which element contains one more proton than one atom of chlorine (Cl)?

• sulfur (S)
• argon (Ar)
• fluorine (F)
• bromine (Br)

The Periodic Table is arranged in rows and columns. From left to right along a row, the atomic number in each column

• decreases by 2.
• increases by 1.
• decreases for gases.
• increases for metals.