Chem Exam 1

milli-

(1/-1000)

micro-

(1/-1,000,000)

centi-

(1/-100)

deci-

(1/10)

mega-

(1/1,000,000)

define the term mole

A mole is a unit of measurement representing the amount of a substance. It is defined 6.022 x 10^23 (Avogadro's number).

what are protons?

Protons are positively charged particles in an atom's nucleus. They determine an element's atomic number and identity.

what are electronswh

Electrons are subatomic particles that carry a negative charge and orbit around the nucleus of an atom.

what are neutrons?

Neutrons are subatomic particles found in the nucleus of an atom. They have no electrical charge and contribute to the mass of the atom.

how do you calculate an elements mass?

The mass of an element can be calculated by adding up the masses of its protons, neutrons, and electrons.

what does the mass number of an element describe?

The mass number of an element describes the total number of protons and neutrons in the nucleus of an atom of that element.

define what an isotope is

An isotope is a variant of an element with a different number of neutrons in its nucleus, resulting in a different atomic mass. Isotopes may have different physical properties but generally behave chemically similarly to the standard form of the element.

define what a cation is

A cation is a positively charged ion formed when an atom loses electrons.

define what an anion is

An anion is a negatively charged ion formed when an atom gains electrons.

explain why the periodic table is organized the way it is

Elements are arranged in order of increasing atomic number, which corresponds to the number of protons in the nucleus. This arrangement allows elements with similar properties to be grouped together in columns called groups or families. The rows are called periods. The periodic table is organized this way to show the trends in properties such as atomic radius, ionization energy, and electronegativity, making it easier to understand and predict the behavior of elements.

describe the “octet rule”

the tendency for atoms to prefer having 8 electrons in its valence shell

how does the octet rule relate to the formation of ions?

atoms gain or lose electrons to achieve a stable electron configuration

what is the formation of ionic compounds?

The formation of ionic compounds involves cations and anions through electrostatic attraction. Ionic compounds are typically formed when a metal reacts with a nonmetal.

what is a covalent compound?

A covalent compound is a chemical compound formed when two or more nonmetal atoms share electrons to achieve a stable electron configuration, resulting in the formation of molecules.

how can you determine the number of valence electrons an atom has based on its position on the periodic table?

The group number of an element tells you the number of valence electrons for that element.

The period number of an element corresponds to the energy level or electron shell that contains its valence electrons.

how can you predict what ion an atom will form based on the number of valence electrons it has?

Atoms with a few valence electrons (1-3) tend to lose those electrons to achieve a stable, empty outer shell, forming positively charged ions called cations. Atoms with many valence electrons (5-7) tend to gain additional electrons to fill their outer shell, forming negatively charged ions called anions.

How can you predict the formula of ionic compounds given two elements (that form ions)?

To predict the formula of an ionic compound given two elements that form ions, you need to determine the charges of the ions formed by each element and then balance the charges to create a neutral compound.

Name ionic compounds

1. Sodium Chloride: NaCl (table salt)

2. Potassium Iodide: KI

3. Calcium Carbonate: CaCO₃ (found in chalk, limestone, and shells)

4. Magnesium Oxide: MgO

How can you use the name of an ionic compound to write the formula for that compound?

You need to know the charges of the ions involved and how they combine to form a neutral compound, then write the elements out.

Name, formula and charge of a hydroxide ion:

• Name: Hydroxide ion

• Chemical Formula: OH⁻

• Charge: The hydroxide ion carries a charge of -1.

Name, formula and charge of a bicarbonate ion:

• Name: Bicarbonate ion

• Chemical Formula: HCO₃⁻

• Charge: The bicarbonate ion carries a charge of -1.

Name, formula and charge of a carbonate ion:

• Name: Carbonate ion

• Chemical Formula: CO₃²⁻

• Charge: The carbonate ion carries a charge of -2.

Name, formula and charge of a phosphate ion:

• Name: Phosphate ion

• Chemical Formula: PO₄³⁻

• Charge: The phosphate ion carries a charge of -3.

Name, formula and charge of a ammonium ion:

• Name: Ammonium ion

• Chemical Formula: NH₄⁺

• Charge: The ammonium ion carries a charge of +1.

Name, formula and charge of a nitrate ion:

• Name: Nitrate ion

• Chemical Formula: NO₃⁻

• Charge: The nitrate ion carries a charge of -1.

How can you predict the formula of an ionic compound given one element and a polyatomic ion?

1) Identify the element

2) Identify the polyatomic ion

3)determine the charges

4)balance the charges

5) write the formulas