atoms and atomic theory

What did Democritus discover from his thinking?

-the difference shapes and sizes of the atom determine the substance

What did John dalton believe?

-chemical reactions are a rearrangement of atoms

-compounds are a combination of 2 or more different atoms

-all matter is made up of atoms

What did JJ Thompson do?

-choco chip cookie model

-atoms are not the smallest form of mass

-atoms contain smaller particles (electrons)

-subatomic particles move

-atoms of same element are composed of the same subatomic particles

What did Rutherford discover?

-gold foil excitement

-atoms are mostly empty space

What did Rutherford predict? Was he right, why?

-the particles would go straight through

-he was wrong

-particles deflected and bounced back, proving there was a dense, positively charged nucleus.

How did Bohr contribute to the atomic model?

-introduced the orbits for electrons

-his model explained the stability of atoms

-atoms gain or loose electrons to transition between energy levels

-max valance electrons is 8

-8 valence electrons is stable

-lowest energy state

Where are protons located in the atom?

Nucleus

Where are neurons located in the atom

Nucleus

Where are electrons located in the atoms

The orbit

What is the charge or protons?

Positive

What is the charge of neutrons?

Neutral

What is the charge of electrons ?

Negative

What is the mass of a proton?

1 Amu

What is the mass of a neutron?

1 amu

What is the mass of an electron?

0 amu

what is being counted with the atomic number?

Number of protons

What happens when you change the number of protons in an element?

The element is changed

How do you calculate the atomic mass of an element?

Average mass of the amu

why are the masses of most elements on the periodic table listed as decimals?

Because the atomic mass is the average of the elements amu

What is an isotope?

Atoms of the same element, but have different numbers of neutrons

What happens when you add a neutron to an Element?

An isotope is added

How do you know what the most common isotope of an element is?

The atomic mass

what are valence electrons and why are they important?

they determine if the atom is stable or not

which subatomic particle is “valence”?

electron

what subatomic particles are counted within the Bohr and Lewis dot models?

Electrons

what are cations?

ions with a positive net charge

When do cations accrue?

when an electron is lost

what is an anion?

an ion with a negative charge

when do anions occur?

when an electron is gained

what is the mass number?

The number of protons and neutrons