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Chemistry Chapter 7
Question | Answer |
---|---|
Ions that are formed from one atom are known as _______. | monatomic ions |
Ionic compounds that absorb water into their solid structure form. | hydrates |
A group of atoms united by covalent bonds is a(n) ________. | molecule |
Ionic compounds are always ________. | electrically neutral |
To form a bond, atoms share _______. | valence electrons |
Which type of formula best specifies how atoms bond in a molecule? | empirical |
A positively charged ion attracts a(n) _______. | cation |
Name 3 properties of Ionic compounds. | -High melting points - Brittle - Good conductors in their liquid state |
What is the electronegativity when 2 atoms are covalent and nonpolar? | 0.4 or less |
What is the electronegativity when 2 atoms are covalent and polar? | 0.4< X < 2.0 |
What is the electronegativity when 2 atoms are ionic? | < 2.0 |
Many common ions have the electron configuration of a noble gas. True or False. | True |
T/F. In a Lew dot diagram, the dots represent [atomic nuclei]. | False. Valence electrons. |
T/F. Negatively charged ions are [cations]. | False. Anions. |
T/F. The atoms that make up a sulfate ion are held together by [covalent] bonds. | True. |
T/F. To emphasize the ratio of ions in a compound, chemists use a [structural formula]. | False. Empirical formula. |
T/F. Atoms share electrons in an [ionic] bond. | False. Covalent |
T/F. [Molecules]are composed entirely of ions. | False. Ionic compounds. |
T/F. The name of the [cation] usually comes first in the name of an ionic compound. | True. |
T/F. A covalent bond may be polar or [ionic]. | False. Nonpolar |
Describe an ionic bond. | Chemical bond between a positively charged ion and a negatively charged ion resulting from the transfer of electrons from one bonding atom to another. |
Describe a covalent bond. | Chemical bond resulting from the sharing of electrons between two bonding atoms. |
Describe an ionic compound. | A compound that is composed entirely of ions. |
Describe a cation. | A positively charged ion. |
Describe an anion. | A negatively charged ion. |
Describe the octet rule. | The rule that states that atoms tend to gain, lose, or share electrons in order to acquire a full set of valence electrons. |
Describe monatomic ions. | One atom ions. |
Describe polyatomic ions. | Two or more atom ions. |
Describe binary ionic compounds. | Compounds that contain the ions of only two elemens. |
Describe an empirical formula. | The formula used to denote the ratio of ions in a compound. |
Describe a molecule. | A group of atoms that are united by covalent bonds. |
Describe a molecular substance. | A substance that is made of only molecules. |
Describe a molecular formula. | The formula used to describe the compostion of a molecular compound. |
Describe a structural formula. | The formula that specifies which atoms are bonded to each other in a molecule. |
Describe Lewis structures. | Based on the Lewis dot diagram for atoms but used to describe covalent bonds. |
Describe an unshared pair. | Pairs of electrons in an atom involved in covalent bonds that are not shared in bonds. |
Single bonds | 2 atoms share exactly one pair of electrons |
double bonds | consists of two pairs of shared electrons |
triple bonds | consists of three pairs of shared electrons |
polar | when one atom is significantly more electronegative than another in a covalent bond |
nonpolar | when 2 atomshave similar or equal electronegativites and they both exert approximately equal pull on the electrons in the bond. |
hydrates | ionic compounds that absorb water into their solid structures |
anhydrous substances | water-free substances |
Why are many elements more stable as ions than they are as atoms? | In their ionic form, they have the same electron configuration as the previous noble gas, which are unreactive. |
Why are some covalent bonds polar and others nonpolar | Because the elements have varying electronegativites. |