Principles of Chemistry - Atomic Structure

Question 1

what is an atom?

Answer 1

an atom is the smallest part of an element

Question 2

what is a molecule?

Answer 2

a molecule is made of a fixed number of atoms covalently bonded together

Question 3

what does an atom consist of?

Answer 3

a central nucleus, composed of protons and neutrons, surrounded by electrons, orbiting in shells (energy levels)

Question 4

what charge do atoms have?

Answer 4

atoms are neutral because the numbers of electrons and protons are equal

Question 5

what is the mass and charge of a proton?

Answer 5

mass: 1
charge: +1

Question 6

what is the mass and charge of a neutron?

Answer 6

mass: 1
charge: 0

Question 7

what is the mass and charge of an electron?

Answer 7

mass: 0 (1/1836)
charge: -1

Question 8

what is an atomic number?

Answer 8

the number of protons in an atom

Question 9

what is a mass number?

Answer 9

the number of protons and neutrons in an atom

Question 10

what is relative atomic mass?

Answer 10

the average mass of an atom compared to 1/12th the mass of carbon-12

Question 11

how do you calculate relative atomic mass?

Answer 11

• Multiply the mass of each isotope by its relative abundance
• Add those together
• Divide by the sum of the relative abundances (normally 100)