chapter 5: atomic structure

Question 1

what are atoms made of?

Answer 1

protons, neutrons and electrons

> subatomic particles

Question 2

what is the relative charge, mass and symbol of a proton, neutron and electron?

Answer 2

proton

charge: +1
mass: 1
symbol: p

neutron

charge: 0
mass: 1
symbol: n

electron

charge: -1
mass: 1/1840
symbol: e

Question 3

what is a proton number?

Answer 3

• also called the atomic number

- since atoms are electrically neutral, the number or protons is the same as the number of electrons

Question 4

what is a nucleon number?

Answer 4

-it is the total number of protons and neutrons in an atom

Question 5

what are isotopes?

Answer 5

• isotopes are atoms of the same element with the same number of protons and electrons
  > BUT different numbers of neutrons

Question 6

how are electrons arranged in an atom?

Answer 6

• around the nucleus in regions known as the electron shells

Question 7

what is the energy level and the number of electrons the first shell can hold?

Answer 7

• it is the closest to the nucleus
  > lowest energy level
• can hold a maximum of two electrons and is always filled first

Question 8

what are the energy levels and the number of electrons the second and third shells can hold?

Answer 8

• increasing levels of energy ( third shell has higher energy than second
• usually hold up to 8 electrons each
• filled in order

Question 9

what is an atom?

Answer 9

• the simplest unit of an element having the same chemical properties of the element