atoms and molecules

Question 1

what are atoms

Answer 1

the smallest particle of an element

Question 2

what is an atom made of

Answer 2

• neutrons
• protons
• electrons

Question 2

properties of a proton (where is it in the atom etc.)

Answer 2

• inside the nucleus
• relative charge: positive
• relative mass: 1

Question 2

properties of a neutron (where is it in the atom etc.)

Answer 2

• inside the nucleus
• relative charge: neutral
• relative mass: 1

Question 3

properties of a electron (where is it in the atom etc.)

Answer 3

• around the nucleus
• relative charge: negative
• relative mass: negligible

Question 3

how do you know when the atom is neutrally charged

Answer 3

when the number of protons and electrons are the same

Question 4

how is the periodic table arranged

Answer 4

by the number of protons the element has

Question 5

what is the other term for proton number

Answer 5

atomic number

Question 6

what is the mass number of an atom

Answer 6

number of protons + number of neutrons in one atom

Question 7

what is an isotope

Answer 7

atoms of the same element that have different number of neutrons (different mass number)

Question 8

on the periodic table, the mass number below the element is in decimal places, how do you find the mass number of the atom then.

Answer 8

round up or down
e.g. boron: mass number on periodic table is 10.811. to find the mass number is to round up. 10.811~~11

Question 9

how to find number of neutrons in an atom

Answer 9

mass number - proton number

Question 10

how to find the number of electrons

Answer 10

• protons
• equals
• electrons
• proton number = number of electrons

Question 11

what information can you obtain from the periodic table

Answer 11

• Number of protons (atomic number) of an element
• Number of electrons (same as the number of protons) in an electrically neutral atom of an element
• The mass number (when we round up or round down the relative atomic mass) of an element

Question 12

what is chemical formula used for

Answer 12

to tell us how many elements are in a compound

Question 13

what is a molecule

Answer 13

A molecule is a group of two or more atoms chemically combined together

Question 14

what is diatomic moleules

Answer 14

• Molecules made of two atoms
• The individual molecules are represented in a certain way

Question 15

when drawing the molecules of a compound, how do you know which atom is bigger

Answer 15

the atom with a bigger mass number

Question 16

what is a valence shell

Answer 16

the outer most shell of the atom

Question 16

what is the max number of electrons in each shell

Answer 16

1st shell: 2
2nd shell: 8
3rd shell: 8
4th shell: 32 (fyi)

Question 16

what is an ion

Answer 16

atoms that have a different number of electrons than protons

Question 17

how are ions formed

Answer 17

Ions are formed when atoms gain or lose electrons

Question 18

what charge does ions have

Answer 18

Ions have either a positive or negative electrical charge

Question 19

when an ion has less protons than electrons, what charge is the ion

Answer 19

negatively charged

Question 20

when an ion has more protons than electrons, what charge is the ion

Answer 20

positively charged

Question 21

what is anion

Answer 21

anions are negatively charged, less protons than electrons

Question 22

what is a cation

Answer 22

Cations are positively charged, more protons than electrons

Question 23

how many electrons will an atom gain or lose

Answer 23

An atom usually gains or loses electrons until the outermost shell is like that of a Noble Gas (Group 18)

Question 24

in the periodic table, what charge would group 1 ions have

Answer 24

positively, 1+
an electron is removed

Question 25

in the periodic table, what charge would group 2 ions have

Answer 25

positively, 2+
electrons are removed

Question 26

in the periodic table, what charge would group 13 ions have

Answer 26

positive, 3+
electrons are removed

Question 27

in the periodic table, what charge would group 15 ions have

Answer 27

negative, 3-
electrons are added

Question 28

in the periodic table, what charge would group 16 ions have

Answer 28

negative, 2-
electrons are added

Question 29

in the periodic table, what charge would group 17 ions have

Answer 29

negative, 1-
an electron is added

Question 30

in the periodic table, what charge would group 18 ions have

Answer 30

no charge (neutral), stable as they have full valence shells

Question 31

why is the relative molecular mass is not a whole number

Answer 31

• isotopes of the same element exist with a different mass number
• the relative molecular mass is the average of all isotops