Atomic Theory

What is the net charge of an atom

neutral

What charge do protons have?

+

What charge do electrons have?

-

What charge do neutrons have?

0

The amount of protons _______ the amount of electrons

equal

Why was the amu developed?

because mass of subatomic particle is extremely small

What is an amu based on?

1/12th the mass of Carbon - 12

What does amu stand for?

atomic mass unit

Each particle in C-12 has _ amu

1

What is the mass of a neutron

1 amu

What is the mass of an electron?

1/1840 of an amu, close to zero

What is the mass of a proton?

1 amu

Where are protons and neutrons located?

nucleus, center of atom

Where are electrons found?

in the electron cloud orbiting around the nucleus

What is the Atomic Number?

tells the number of protons for all atoms of an element

What is a symbol?

an abbreviation of an element’s English/Latin name

What is the Atomic Mass Number?

tells the number of protons + the number of neutrons for the most common (average) isotope of an element

What is the Mass Number?

the atomic mass number rounded off to the nearest whole number

What is the mass of an amu precisely?

1.673 × 10⁻²⁴ grams

What is the role of the proton?

to determine element

What is the role of a neutron?

to determine isotope

What is the role of the electron?

for chemical activity