[WEEK 06] Atoms and Molecules, Avogadro's Number and Mole Concept

Atomic symbol

A unique name and symbol is used to represent each element

Atomic symbols are based on the ff:

Elemental properties, derived from names of famous scientists, places, astronomical bodies, or mythological characters

Elemental symbols consist of

one capital letter or a capital letter followed by a lowercase letter

Latin term for Silver (Ag)

Argentum

Latin term for Gold (Au)

Aurum

Latin term for Copper (Cu)

Cuprum

Latin term for Iron (Fe)

Ferrum

Latin term for Mercury (Hg)

Hydragyrum

Latin term for Potassium (K)

Kalium

Latin term for Sodium (Na)

Natrium

Latin term for Lead (Pb)

Plumbum

Latin term for Antimony (Sb)

Stibium

Latin term for Tin (Sn)

Stannum

Latin term for Tungsten (W)

Wolfram

The human body is made up of

chemical elements

The elements in the body are in the form of

compound molecules or ions

The most abundant element in the body in terms of mass is ____ because the body contains a lot of water-based fluids

oxygen

Percentage of oxygen and hydrogen by mass in the body

89% and 11% respectively

Almost 99% of the total mass of the human body consists of six elements:

oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus

About 1% is made up of another four elements:

potassium, sulfur, sodium, and chlorine

Each elemental symbol represents one atom of the element and if more than one atom is present in the compound, then a subscript follows the elemental symbol

Compound formula

Methane molecular formula

CH4

Hydrogen peroxide molecular formula

H2O2

Atoms are made up of three subatomic particles

Protons, neutrons, and electrons

Protons and Neutrons

Tightly bound together to form the central portion of an atom called the nucleus

Electrons

Located outside the nucleus and move rapidly throughout a relatively large volume of space surrounding the nucleus

Atomic Number of An Atom

Equal to the number of protons in the nucleus and the number of electrons in an atom

Symbolically represented by Z

Atomic Number of An Atom

Mass Number of An Atom

Equal to the sum of the number of protons and neutrons in the nucleus of an atom

Symbolically represented by A

Mass Number of An Atom

Isotopes

Atoms that have the same number of protons in the nucleus but different numbers of neutrons

Symbolically represented by E

Elemental symbol

Atomic Mass Unit is used to express the

relative masses of atoms

1 u is equal to ____ the mass of a carbon-12 atom

1/12

Molecular Weight

Calculated by adding together the atomic weights of the atoms in the molecule

Average relative mass of atoms are

atomic weight of elements that occur as mixtures of isotopes

Average mass of each particle in a group of atoms is obtained by

dividing the total mass of the group by the number of particles in the group

1 mol is equal to

6.022 x 10^23

Avogadro’s Number

Number of atoms or molecules in a specific sample of an element or compound

Mole (mol)

Number of particles contained in a sample of an element or compound with a mass in grams

Can be used to obtain factors that are useful in chemical calculations involving both elements and compounds

Mole concept

Represents the numerical relationships that exist among atoms in a compound

Chemical formula

Formula for the Atomic Weight of Isotopes

atomic weight = (Isotope A%)(mass of Isotope A) + (Isotope B%)(mass of Isotope B) / 100

Protons

Atomic number

Neutrons

Mass number - atomic number

Electrons

Atomic number - Element charge

Formula to identify atomic number using given number of electrons

e- = atomic number - charge

Overall charge if element gains electrons

-1

Overall charge if element loses electrons

+1

Different number of protons

Different number of elements

Different number of neutrons

Different number of isotopes

Different number of electrons

Different number of ions

An atom is neutral if

number of protons and electrons are the same

Atomic number formula

protons + neutrons

Neutrons have a charge of

0

A neutron has a mass of _____ in g

1.67 × 10^-24

A neutron has a mass of _____ in u

1

An electron has a mass of _____ in g

9.07 × 10^-28

An electron has a mass of _____ in u

1/1836

A proton has a mass of _____ in g

1.67 × 10^-28

A proton has a mass of _____ in u

1

Electrons have a charge of

-1

Protons have a charge of

+1

Subatomic particle located inside the nucleus

Proton and neutron

Subatomic particle located outside the nucleus

Electron

Distance of the closest electrons would be at least ___ away

80 meters