IPC 1.3 Properties of Matter

Helium and neon are gases that are unreactive. What makes these elements unlikely

to react?

• the number and placement of the protons

• the number of isotopes of the atom

• the number of valence electrons

• the number of energy levels

Which statement best describes the reason for nitrogen’s reactivity?

• Nitrogen is reactive because its outer electron shell is incomplete

• Nitrogen is reactive because its outer electron shell is full

• Nitrogen is unreactive because its outer electron shell is incomplete

• Nitrogen is unreactive because its outer electron shell is full

A student is studying magnesium, a highly reactive element that is essential to cells of all living organisms.

Which characteristic of magnesium is most closely related to its chemical reactivity?

• the 12 protons in each atom of magnesium

• the density of magnesium

• the atomic mass of magnesium

• the two valence electrons in each atom of magnesium

The atoms of a certain element each contain 17 protons and 7 valence electrons.

Which statement correctly identifies the element and describes its chemical reactivity?

• The element is chlorine, and it is highly reactive

• The element is manganese, and it is not very reactive

• The element is chlorine, and it is not very reactive

• The element is manganese, and it is highly reactive

Why is potassium more likely to react with another element than an element such as argon?

• potassium has one more proton than argon

• potassium has two fewer neutrons than argon

• potassium has one more electron than argon

• potassium has one more energy level than argon

The atomic number of neon is 10. Therefore, which of the following is most correct about an atom of neon?

• It is unreactive

• It has 8 electrons in its outer electron shell and it is unreactive

• It has an atomic mass of 10 daltons.

• It has 8 electrons in its outer electron shell.

Atoms whose outer electron shells contain 8 electrons tend to

• be highly reactive

• be fairly stable

• be stable and chemically nonreactive, or inert.

• form ions

Which of theses elements is the MOST reactive?

Hint:

most reactive metals = Group 1

most reactive non metals = Group 17

• boron

• carbon

• sulfur

• chlorine

The reactivity of an atom arises from

• the average distance of the outermost electron shell from the nucleus.

• the existence of unpaired electrons in the valence shell.

• the sum of the potential energies of all the electron shells.

• the potential energy of the valence shell.

Neon and other elements in group 18 rarely enter chemical reactions and rarely form compounds with other elements.

Which statement BEST explains why these elements almost never react?

• These elements are so rare that they seldom come into contact with other

  elements and compounds.

• These elements have the most stable outer energy levels of all the elements,

  with eight valence electrons and a small atomic radius.

• These elements occur only in the extreme upper level of Earth’s atmosphere,

  where pressure is too low for chemical reactions.

• Atoms of these elements form very stable covalent bonds with identical atoms

  of the same element, which prevents reactions with other elements.