Fundamentals of Chemistry

➤ smallest and simplest form of matter that gives uniqueness to elements.

➤ Inside the central nucleus are the subatomic particles

combination of two or more atoms

general term (moving)

protons, neutrons, and electrons

anything that has mass & volume and that occupies space.

are composed of one type of atom.

can see the different parts of the mixture easily/ visible.

can see the different parts of the mixture easily/ visible.

1. Identify the problem.

2. Gather enough information.

3. Formulate Hypothesis.

4. Test the hypothesis.

5. Recording and Analyzing Data.

6. Make a Conclusion.

7. Verification of Conclusion.

A pure substance consisting of two or more elements with a definite composition, that can be broken down into simpler substances only by chemical methods

Three forms of matter: solid, liquid, and gas

The weighted average mass of all the naturally occurring isotopes of an element

1. All matter is made up of tiny particles.

2. There is empty space between the particles.

3. The particles are in constant motion.

4. There are forces that act between the particles

have a definite shape and volume

have a definite volume, but take the shape of the container.

have no definite shape or volume.

are the appearances of an object, they can vary in size, shape, texture, color or mass.

independent of the amount of materials; can be measured.

not independent (texture, color) and no measurement.

change in the appearance of one matter (shape, size or state but not composition).

the chemical composition of an object.

reaction or change of the composition of a matter with another substance.

➤ Atoms are building blocks of elements.

➤ Similar atoms are in each element

➤ 2 or more bond to create compound with the ratio ( 1 : 2 : 1)

show the mass number and atomic number

are atoms that have the same atomic number, protons or elements but different mass numbers and neutrons.

the weight average mass of all the atomic masses of the isotopes of the atom. It is the result of when you round off the atomic weight^2 in your periodic table.

Example of an average atomic mass:

Chlorine: Cl-35 is about 75.5% and Cl-37 is 24.5% of natural chlorine.

35 × 75.5/ 100 = 26.4

37 × 24.5/ 100 = 9.07

are the counts of protons and neutrons.

◆ Mass number (MN) = p+ (protons) + n (neutrons)

◆ n (neutron) = MN (mass number) - p+ (protons)

◆ p+ (protons) = the atomic number of an element

◆ e- (electrons) = p+ (protons) - charge

An atom is neutral

If the atoms are neutral = net charge is zero = number of protons is equal to electrons.

Atomic number will be equal to the number of electrons if neutral.

➤ An atom is neutral.

➤ If the atoms are neutral = net charge is zero = number of protons is equal to electrons.

➤ Atomic number will be equal to the number of electrons if neutral.

➤ Is a quantitative observation

➤ Is the process of getting the actual measure of an object dimension's property in comparison with a standard unit of acquiring a value.

➤ Two parts: number and scale (unit)

include digits which are certain + 1 uncertain digit.

always count as significant figures.

zeroes that precede all nonzero digits; don’t count as significant figures; only function is to know the decimal position/place of a number.

● Ex: 0.0025 > only 2 and 5 is the significant numbers

zeroes between nonzero digits; counts as SF.

● Ex: 1.008 > we have four significant figures

zeroes right end of the number; significant only if the number has a decimal point.

● Ex: In 100 > only 1 is the SF, but if it is written as 100. then we’ll have three SF.

● Another example is in 1.00 x 10^2 > we’ll have three SF

◆ Not obtained using measuring devices but by counting; example 10 experiments or 3 apples.

◆ Can be assumed to have infinite numbers of significant figures; example is the circumference of a circle or the volume of a sphere.

◆ Can also arise from definitions; example 1 inch is defined by 2.54 cm, neither of the numbers are the limit of significant figures when calculated.

the British system of measurement was first adopted in England and later became widely used in the United States; also known as the FPS system, derived from the names of the standard units of length (foot), weight (pound), and time (second)

this system also include the inch, yard, mile, and horsepower

originated in France in 1791; has the units of meter, centimeter, kilogram, and second

the commonly used method of measurement the modern metric system has been officially named and known worldwide as the International System of Units

are the fundamental units like meters, kilograms and seconds and are also the standard units for length and time, respectively.

- However, for smaller quantities, centimeters, grams and seconds are used as fundamental units.

these are quantities that emanate or are a result of the combination of fundamental quantities after a set of operations.

Given unit × Desired unit = Desired unit

Given unit

A number in scientific notation has two parts: the first is a number between 1 and 10 (N), and the second part is a power of 10 (N^10).

chart in which elements having similar chemical and physical properties are grouped together.

○ Period = horizontal

○ Groups/ Families = vertical

good conductor of heat and energy; positively charged.

poor conductor of heat and energy.

has properties that are intermediate between those of metals and non-metals.

Group 1A elements ( Li, Na, K, Rb, Cs and Fr)

Group 2A elements (Be, Mg, Ca, Sr, Ba and Ra)

Group 7A (F, Cl, Br and At)

Group 8A (He, Ne, Ar, Kr, Xe and Rn

happens when we have electrical discharge

○ Example: Getting grounded after friction on a carpet then holding onto a metal thing.

○ A short circuit can happen after getting electrified and that causes death (Example is getting struck by lightning).

2 or more atom bonded chemically

○ Diatomic Molecule = only 2 atoms

○ Polyatomic Molecule = more than 2 atoms

a group of atoms that has net positive or negative charge.

ion with a positive charge

ion that has a negative charge because of an increase in the electrons.

only 1 atom

more than 1 atom

expresses composition of molecules and ionic compounds in terms of chemical symbols.

exact numbers of atoms of each element in the smallest unit of a substance.

■ All tropes, one of 2 or more distinct forms; can be affected by light, temperature and pressure.

how atoms in a molecule are bonded to one another.

used to visualize

Space-Filling Models - atoms = by overlapping spheres, proportional in size to the corresponding atoms; no bonding and mostly emphasizes on molecule size.

Empirical Formula - always in proportion or ratio; written by reducing subscripts in molecular formulas to the smallest possible whole numbers.

compounds formed from cations and anions

Formulas for Ionic Compounds are usually the same as their empirical formulas because they do not consist of discrete molecular units. For the formula to be electrically neutral, the sum of the charges on the cation and anion in each formula must be ZERO.

● n (energy levels/ shells) = principle of quantum numbers

Formula: 2(n)^2

n2 = 2(2)^2 = 8 electrons

Shells hold only specific numbers of electrons.

● Orbitals can also hold a certain number of electrons.

○ Electrons in orbitals = n x 2