Chapter 3 Flashcards
(37 cards)
What is the difference between elements, compounds, and mixtures?
Elements are pure substances, compounds are combinations of elements chemically bonded, and mixtures are combinations of substances physically combined.
How is a covalent bond formed?
By sharing a pair of outer electrons between two atoms.
How is an ionic bond formed?
By the strong electrostatic force of attraction between oppositely charged ions.
Give 2 examples of giant covalent structures.
Diamond and graphite.
What type of attraction is metallic bonding?
Electrostatic attraction.
What particles are attracted in a metallic bond?
Positive ions in the metallic lattice and a ‘sea’ of delocalized electrons.
Which groups of the periodic table primarily form covalent bonds?
Group IV - VII (non-metals).
What is the main characteristic of Group VIII elements (inert gases)?
They have a full outermost shell of valence electrons.
What is the octet rule?
Atoms attempt to gain, lose, or share electrons to achieve a stable octet electron arrangement.
Where do chemical bonds form?
During a chemical reaction between atoms of the same or different elements.
What types of covalent bonds exist?
Single, double, and triple bonds.
Describe a single covalent bond.
Two atoms share one pair of electrons.
Describe a double covalent bond.
Two atoms share two pairs of electrons.
Describe a triple covalent bond.
Two atoms share three pairs of electrons.
What is the definition of a covalent bond?
Chemical bonding formed by the sharing of one or more pairs of electrons between two atoms.
In a pure sample of an element, what is the most important feature of all the atoms present?
All atoms have the same number of protons (and electrons).
What type of elements typically react to form ionic bonds?
A metal and a non-metal atom.
What is an ion?
An electrically charged atom or group of atoms formed by the loss or gain of electrons.
What do metals do with electrons to become more stable?
Lose electrons to form positive ions.
What do non-metals do with electrons to become more stable?
Gain electrons to form negative ions.
What type of compounds have high melting and boiling points?
Ionic compounds.
Why do simple covalent compounds have low melting and boiling points?
The intermolecular forces between the molecules are very weak.
Why don’t simple covalent compounds conduct electricity?
There are no free electrons or ions present.
Why do ionic compounds have high melting and boiling points?
Ions are attracted to each other by strong electrostatic forces.
