CH 6 CHEM TEST (Chemical Bonds)

What other name is sometimes given to ionic bonds?

electrovalent bond

Explain why ionic compounds are formed when a metal bonds with a nonmetal but covalent compounds are formed when two nonmetals bond.

(Ionic) When a metal bonds with a nonmetal, electrons are *transferred* from the metal to the nonmetal because metals have very low electronegativities and non metals have high electronegativities (Nonmetals are strong - steel electrons). (Covalent) Because nonmetals tend to have similar high electronegativities, neither atom can take electrons from the other, forcing them to *share* electrons* (neither strong enough to steal electrons so they share).

What is the reason atoms bonds with each other: valence electrons and energy

(VE) to form an octet and become stable. (energy) Decrease potential energy (PE) high to low energy.

Nonpolar covalent bond

*NonP:* even sharing of electrons, symmetrical electron density, and identical atoms.

Polar covalent bond

*Polar:* Uneven sharing of electrons, asymmetrical electron density, partial charges (δ+ & δ- dipole).

List 2 rules used to determine which atom will be the central atom of the dot diagram of a chemical formula.

(1) The atom with the lowest subscript (ex: *C*F₄). (2) The atom that forms the most bonds (only used if there are two or more elements: ex: HCIO: O bc it has 2 bonds while H & CI have 1).

Explain how a molecule with polar bonds can be non polar.

If the polar bonds are symmetrically arranged around the central atom, the molecule will be non polar (no poles). Because the dipole moments will cancel out.

Is Concrete made of primarily ionic or covalent compounds?

Ionic (Solid and brittle when hit w/ hammer).

What type of bond will usually be formed between a metal (other than hydrogen) and a nonmetal?

ionic bonds

A triple bond is where ___ pairs of electrons (a total of ___ electrons) is shared between two different atoms. It is usually ____ in strength than a double or single bond.

3, 6, greater

Define polyatomic

A covalently bonded group of atoms with a charge. (An ion that contains more than one atom)

Define Ionic bond

A force of attraction that result when electrons are transferred from one valence shell of one atom to the valence shell of another atom (ex: [k+] :[F-]).

Define electronegativity (hogging electrons)

Attraction an atom has for a shared pair of electrons. (2) Higher EN atom: δ⁻ (hogs electron) (ex: HCI, CI is the hogger: 3.0) (3) Lower EN atom: δ⁺

List 3 differences between ionic bonds and covalent bonds

C: share electrons, prefixes (di), Hydrogen w/ nonmetal or 2 nonmetals (medium force of attraction). I: transfers electrons, Roman Numerals (II), metal (other than Hydrogen) & nonmetal (strong force of attraction).

A molecule refers SPECIFICALLY to substances that have ____ type of bond

Covalent

What type of bonding will always be present between 2 nonmetals?

Covalent

Is Gasoline made of primarily ionic or covalent compounds?

Covalent (liquid)

Is Candy Corn made of primarily ionic or covalent compounds?

Covalent (soft solid)

What type of bond will usually be formed between hydrogen and nonmetal or between two nonmentals?

Covalent bonds

Define Covalent bond

Force of attraction between atoms that results when electrons are shared between two atoms (H & NM or 2 NM's) (called INTRA molecular forces).

Properties of Ionic Compounds

Hard, Brittle, high melting and boiling points, conduct electricity only when dissolved in water.

The type of bond that holds together a diatomic molecule of fluorine is called ____

Nonpolar Covalent

What are partial charges?

Partial charges are created due to the *asymmetric* distribution of electrons in chemical bonds. (ex: in a polar covalent bond like HCl share electrons)

Properties of Covalent Compounds

Soft, liquid, flammable, low melting and boiling points, don't conduct electricity, don't dissolve well in water

What does electronegativity have to do with bond polarity?

The type of bond (ionic, non polar/ polar covalent) can usually be calculated by finding the difference in EN of the two atoms that are going together (subtraction). ∆EN (e- difference) = high EN - lower EN). The higher the e- difference the more polar the bond.

Why can water dissolve many ionic compounds

The δ+ ends of H2O molecule are attracted to the negative ion in the crystal while the δ- end of the H2O molecule are attracted to the positive ion in crystal. This attraction pulls the ions out of structure

How can you determine the number of bonds an atom will form? Be specific

Use Roman Numeral: for metals: Roman Numeral = # bonds on s&p section. For nonmetals: δ- - RN= # bond formed.

Where are the s & p electrons located on an atom with a lewis dot diagram?

on right of an atom is S section (electrons), and left of an atom is P section (electrons).