Atomic Structure

Atoms are made of protons, neutrons, and electrons.

The electrons are located outside the nucleus in the electron cloud.

​The nucleus is in the center of the atom and contains the neutrons and protons.

Protons carry a positive charge.

Neutrons carry no charge.

Electrons carry a negative charge.

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Atomic Structure

A closer look

An ion is a charged particle

●Different ions have the same number of

protons but different number of electrons

Anion: negatively charged ion

●Formed when atoms gain electrons
●More electrons than protons
●Nonmetals usually form anions

Anion: negatively charged ion

● Formed when atoms gain electrons
● More electrons than protons
● Nonmetals usually form anions
● Name is changed if it is a monoatomic ion (not a polyatomic) ending is changed to -ide

1. The Ion
Cations: positively charged ions

● Formed when atoms lose electrons
● More protons than electrons
● Metals usually form cations
● Name doesn't change unless roman numerals are used for the charge (Transition metals)

Representing the Atom

A. Hyphen Notation

a. Used to represent neutral atoms
b. Ex:

i. Carbon-14
ii. Nitrogen-15
iii. Uranium-235

1. The Isotope
Isotope: two or more of the same element with
different mass numbers
● Isotopes are naturally occuring
● Different isotopes have the same number of protons

but different number of electrons

Nitrogen-14
Nitrogen-15

Element Name

• Find this on the periodic table to find the number of protons

• Since it is a neutral atom, # of p⁺ = # of e^-

Mass Number

• Mass # = p⁺ + n⁰

• You can use this number to find the number of neutrons in the atom (n⁰ = mass # - p⁺)

Representing the Atom

• Nuclide Notation OR Nuclear Symbol

  • Used to represent neutral atoms OR ions

  • Examples ¹⁴₆C or ⁶Li¹⁺

Mass Number
● Use this to find the

number of neutrons

Mass Number
● Use this to find

the number of
neutrons

● Mass # = p+ + n0

Atomic Number or Element Symbol
● Tells you the number of p+

● An atomic number will not always

be listed

● If the atomic number is not listed,

look for the symbol on the PT

Charge of Ion
● Use this to find

the number of
electrons

● Charge = p+- e-

● If there is no

charge listed,
assume it is 0

​Mass Spectrometry & Average Atomic Mass

Some text here about the topic of discussion

Include

• rough drawing of the graph

• Include example problem

​Set up your notebook

Some text here about the topic of discussion

LL 4.__ Lab Average Atomic Mass. Group Members:__________

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Pre-lab Discussion​: (leave about 2 inches)

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Part 1: Lab Data​ / and Calculations

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​Post Lab Questions:

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