Chemistry Chap. 18

Flashcards based on lecture notes about chemical bonds, compounds, and formulas.

What is a chemical compound?

A substance formed from two or more elements in which the exact combination and proportions of elements is always the same.

What does a chemical formula show?

It shows what elements a compound contains and the exact number of atoms of each element in a unit of that compound.

What is a chemical bond?

The force that holds atoms together in a compound.

Why is sodium chloride not like the elements that form it?

Because when sodium loses one electron and chlorine takes that one, they both have a stable outer energy level.

What does silicon dioxide contain?

One atom of silicon and two atoms of oxygen.

What can be learned about an element from its electron dot diagram?

How many electrons are in its outer shell.

How do atoms form a chemical bond?

When atoms gain, lose, or share electrons, an attraction forms between the atoms, pulling them together to form a compound. The attraction is called a chemical bond, which is the force that holds together atoms in a compound.

What is an ion?

An atom or molecule with an electrical charge.

What is an ionic bond?

The attraction between positively and negatively charged ions.

What is a covalent bond?

The attraction that forms between atoms when they share electrons.

What is a molecule?

A group of atoms held together by covalent bonds.

What is a polar molecule?

A molecule that has a slightly positive end and a slightly negative end because electrons are not shared equally.

What is a nonpolar molecule?

A molecule that does not have oppositely charged ends.

How many electrons does a potassium atom have in its outer shell?

one electron in its outer shell, which is why it’s so reactive

What does the potassium atom do with tat one electron when it combines with an element?

Loses its, turning into a positive ion

How is a covalent bond formed?

Sharing electrons between two nonmetal atoms.

What are nonpolar covalent bonds?

Nonpolar covalent bonds are formed when two nonmetal atoms share electrons equally, resulting in a balanced distribution of electrical charge.

what are polar covalent bonds?

when two nonmetal atoms share electrons unequally, leading to a partial positive charge on one atom and a partial negative charge on the other.

What’s an ion?

And atom that has gained or lost electrons

What’s the oxidation number?

The positive or negative number that shows how many electrons have been gained or lost to become stable.

What is a binary compound?

A two element formula

What is a polyatomic ion?

Covalently bonded group of atoms that is either positively or negatively charged with two or more atoms

What does hydrate mean?

a compound that has water chemically attached to its atoms and written into the chemical formula

What is the oxidation number and charge for sodium?

The oxidation number is 1+ and the charge is positive

What is the charge and oxidation number for chlorine?

The oxidation number is 1- and the charge is negative

What does an oxidation number of 1+ mean?

To lose one electron

What are the steps for writing a formula for and ionic compound?

Write the the symbol of the one that has a positive oxidation number of charge, writes down the symbol of the element with a negative oxidation number, and then find the least common multiple of the charges of each ion

How can water be removed from the hydrate crystals?

By heating heat up

What does it mean to be anhydrous?

The compound doesn’t have water

What is CaSO₄·2H₂O chemical name?

Calcium sulfate dihydrate

What is CaSO₄·2H₂O common name?

Gypsum aka plaster of Paris

How many capital letters are in elements chemical symbol?

One

What is a subscript?

Shows number of each type of atom in a unit of that compound

What does the 2 in Mg(OH)₂ mean?

2 groups of (OH)

What is the octet tule?

When atoms like to have exactly eight electrons in their outer shells

What is a covalent bond?

When two non metal atoms are sharing electrons

What is the prefix for one atom?

Mono-

What is the prefix for two atoms?

Di-

What is the prefix for three atoms?

Tri-

What is prefix for four atoms?

Tetra-

What is the prefix for five atoms?

Penta-

What is the prefix for six atoms?

Hexa-

What is the prefix for seven atoms?

Hepta-

What is the prefix for eight atoms?

Octa-