Unit 2 Practice

Which characteristic explains why helium, neon, and argon do not tend to form chemical bonds with other elements?

• Their outermost electron shells are completely filled
• They are gases at room temperature

• They are rare in Earth’s crust

• They have the smallest atomic radii

What do sodium (Na) and argon (Ar) have in common, and how do they differ based on their positions on the periodic table?

• Both are in the same group, so they have the same number of valence electrons
• Both are in the same period, so they have the same number of electron shells, but sodium is more reactive
• Both are in the same period, so they have similar chemical properties
• Both are in the same group, so they have the same number of protons

Which of the following statements is true about phosphorus (P), sulfur (S), and neon (Ne)?

• Phosphorus and sulfur are in the same group, so they have similar properties
• Sulfur and neon are both noble gases
• Sulfur and phosphorus have the same number of valence electrons
• Phosphorus and sulfur are in the same period, so they have the same number of electron shells

An unknown element is identified as a very reactive metal. Based on its properties and position on the periodic table, which group is it most likely to belong to?

• Group 18, the far-right column

• Group 17, the second-to-last column

• Group 14, near the center of the table

• In group 1, the first column on the left

Which element is most chemically similar to argon (Ar)?

• Helium (He)
• Oxygen (O)
• Sodium (Na)
• Sulfur (S)

Tags

NGSS.MS-PS1-1

As you move from left to right across a period on the periodic table, what trend is observed?

• Elements become less stable
• Elements change from metals to nonmetals
• Elements become more reactive
• Elements change from gases to solids

A neutral atom of magnesium (Mg) has an atomic number of 12 and an atomic mass of 24. How many protons, electrons, and neutrons does it have?

• 12 protons, 12 electrons, 24 neutrons
• 24 protons, 12 electrons, 12 neutrons
• 12 protons, 12 electrons, 12 neutrons

Tags

NGSS.MS-PS1-1

What does the atomic number of an atom tell you?

• The total number of protons and neutrons
• The number of electrons in all atoms
• The number of neutrons
• The number of protons in the atom

What is a metalloid?

• An element with properties of both metals and nonmetals
• An element that is only found in nature
• An element with the same number of protons and electrons
• An element that is always a gas at room temperature

Which part of the periodic table contains the majority of elements that are shiny, good conductors of electricity, and malleable?

• On the right side
• On the left side
• Only in periods 5 and 6
• Only at the top row