chapter 1.3 and 1.4

Question 1

what is an atom made off?

Answer 1

made up of

• a small positively charged nucleus containing two subatomic parts- positively charged protons and neutral neutrons
• surrounded by an larger cloud of neagtively charged electrons.

Question 2

electrons

Answer 2

• negatively charged particles
• froms cloud of negativity around nucleus
• cloud gives atom size and volume
• electron = 1800 time smaller than a proton or neutron
• space occupied by cloud of electrons = 10000 -100 000 times larger than a nucleus

Question 3

what does electrostatic attraction state?

Answer 3

negative particles attract positive particles

• electrons are bound to the nucleus by the electrostatic attraction to the protons within the nucleus.
• the charge on an electron is equal but opposite to the charge of a proton.
• electrons are said to have a charge of a -1 whereas protons have a charge of +1

Question 4

What is a nucleon(s)

Answer 4

The subatomic particles in the nucleus, the protons and neutrons, are referred to collectively as nucleons.

Question 5

The nucleus

Answer 5

• nucleus of an atom is approximately 10 000 - 100 000 times smaller than the size of an atom
• nucleus contributes around 99.97% of the atoms mass (means that atom nuclei are extremely dense)

Question 6

Protons and neutrons

Answer 6

Protons are positively charged particles with a mass of approximately 1.673 × 10–27 kg. Neutrons are almost identical in mass.

Question 7

What is Rutherford known for?

Answer 7

New Zealand 1899-1911

• gold foil experiment

Question 8

What are the four things Rutherford’s gold foil experiment suggested

Answer 8

• Most of the mass of an atom, and all of the positive charge must be located in a tiny central region called the nucleus.
• Most of the volume of an atom is empty space, occupied only by electrons.
• The electrons move in circular orbits around the nucleus.
• The force of the attraction between the positive nucleus and the negative electrons is electrostatic.

Question 9

how to find the mass number

Answer 9

protons + neutrons

Question 10

what does electrically neutral mean

Answer 10

number of protons + electrons are equal

Question 11

what does the A,Z,X in a structure of atom stand for?

Answer 11

A= mass number
Z= atomic number
X= symbol of element

Question 12

what are isotopes?

Answer 12

atoms that have the SAME number of protons (atomic number)

BUT
DIFFERENT number of neutrons (different mass number)

Question 13

property of isotopes

Answer 13

• have IDENTICAL chemical properties
• Different physical properties such as mass and density a
  in particular some isotopes are radioactive.