Chemistry I H Exam Review

What is the law of conservation of matter?

• Matter changes when reacted or changed.
• The mass of all reactants are changed during a physical or chemical change.
• The mass of the reactants is the same as the mass of the products.
• The mass of the products is different than the mass of the reactants.

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The atomic number of oxygen is

• 8

• 15.9994

• 16

• O

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Electrons are

• Positively charged particles

• Negatively charged particles

• Neutral

A group of elements that are shiny, conduct heat and electricity well is called

• Metals

• Non-metals

• Metalloids

In the atom diagram shown, E is pointing to

• An electron
• a proton
• a neutron
• the nucleus

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What is a valence electron?

• an electron that is found in the outermost orbital of an atom. 
• an electron found in the innermost orbital of an atom.
• an electron found in the middle orbital.

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An ionic bond forms when

• valence electrons are shared back and forth (move between) two atoms.

• a sea of mobile electrons surround the cations and they then become negativly charged

• valence electrons are transferred from one atom to another, forming charged ions that are then pulled together by attraction between opposite charges

• none of the above

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Covalent bonds form when

• the electronegativity difference between two atoms is very large.

• electrons are completely transferred between two atoms.

• pairs of electrons are shared between two atoms.

• ions are held together by opposite charges.

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• Periods
• Groups

• Periods
• Groups