atomic structure

Proton

A positively charged subatomic particle located in the nucleus

Proton symbol

$$p^{+}$$

Proton charge

1+

Proton relative mass

1 amu

Proton actual mass

$1.673\cdot10^{-27}$Kg

Neutron

A neutral subatomic particle located in the nucleus

Neutron symbol

$$n^0$$

Neutron charge

0

Neutron relative mass

1 amu

Neutron actual mass

$1.675 \times 10^{-27}\,\text{kg}$.

Electron

A negatively charged subatomic particle located in the electron cloud

Electron symbol

$$e^{-}$$

Electron relative mass

≈ 0 amu or 1/1836 amu

Electron actual mass

$9.109 \times 10^{-31}\,\text{kg}$.

Electron charge

1-

The atomic mass unit (amu)

A relative mass scale that compares every atom to a standard reference atom

Reference atom used for comparison

Carbon-12

What does 1 amu equal?

1/2 of the mass of one carbon-12 atom

What are the 2 regions of the atom?

Nucleus and electron cloud

The nucleus

Contains protons and neutrons, Overall charge is positive, and hold almost all of the atom’s mass

The electron cloud

Contains electrons, the charge is negative, and holds almost all of the atoms of volume

How do you describe the overall size of an atom?

About $10^{-10}$ m across

How does the size of the nucleus compared to the size of an electron cloud?

1/100,000 ; marble at the center of a stadium

Atomic number (Z)

The number of protons and the number of electrons in a neutral atom

What does the atomic number determine?

Which element an atom is

Mass number (A)

The sum of protons and neutrons p + n

How do you find the number of neutrons?

Mass number - atomic number A - Z

What is the number of electrons determine in an atom?

The charge of the atom

What does the number of protons in one atom determine?

The atoms identity

Hyphen notation

Write the element name followed by its mass number

Nuclear symbol

Write the mass number above the atomic number to the left of the element symbol

Ion

Atoms are neutral particles because they have the same number of positive protons and negative electrons, Charged particle

How are ions formed?

When an atom gains or loses electrons

How is a negative (anion) formed?

When the atom gains negative electrons

How is a positive (cation) formed?

When an atom loses negative electrons

Example of a negative ion (anion)

$$F\rightarrow F^{-1}$$

Example of a positive ion (cation)

$$Na\rightarrow Na^{+1}$$

Isotope

Atoms of the same element (Same number of protons, but different number of neutrons)

Example of a isotope

Lithium-7 has 3 protons and 4 neutrons, while Lithium-6 has 3 protons and 3 neutrons

Average atomic mass

The weighted average of all the isotopes of that element

What is the average atomic mass based on?

Mass number of the isotope and percent abundance

Percent abundance

How much actually exists in nature

How do you know which isotope is the most abundant in nature?

Whenever the mass number is closest to the average atomic mass

Can you determine what the element is with the number of protons?

Yes

Can you determine what the element is with the number of neutrons?

No

Can you determine what the element is with the number of electrons in a neutral atom?

Yes

Can you determine what the element is with the number of electrons?

No

When an ion has a negative charge, what happens to the electrons

They increase

When an ion has a positive charge, what happens to the electrons

They decrease