Unit 1

Question 1

Mass number

Answer 1

number of protons + number of neutrons

Question 2

Solids

Answer 2

Fixed 3d lattice, attractions between particles are very strong (high melting point). Particles only vibrate, do not move out of their fixed positions.

Question 3

Substance

Answer 3

Substance is a form of matter with distinct properties, where they differ from one another in composition. Has a distinct chemical formula.

Question 4

Mixture

Answer 4

A mixture is a combination of two or more substances. Does not have constant compositions, thus cannot write a chemical formula.

Question 5

Compound

Answer 5

A substance made of two or more different atoms.

Question 6

Element

Answer 6

A substance composed of only one type of atom.

Question 7

Subatomic particles

Answer 7

Subatomic particles include protons, neutrons, and electrons. The protons and nucleus form the nucleus of the atom, a dense positively charged core. All atoms are neutral.

Question 8

Atomic radius

Answer 8

The distance from the nucleus to the valence shell. Determined by how strongly outer shell electrons are held by the nucleus. Increases down a groups decreases across a period.

Question 9

Metallic Character

Answer 9

The ability of an atom to lose electrons is referred to as a metallic character. As elements lose outer shell electrons the more easily they behave like metals. Follows the same trends as the atomic radius.

Question 10

Electronegativity

Answer 10

The ability of an atom to gain an electron. Opposite trends of metallic character.

Question 11

Gas

Answer 11

particles are far apart, disordered and move in a random fashion, very fast. particles collide, the volume isn’t constant and attraction is the weakest.

Question 12

Shells

Answer 12

Major energy levels in which electrons are located.

Question 13

Subshells

Answer 13

Subshells are found within shells. They are given the labels s,p,d,f in increasing energy levels. Each Subshell has a different amount of orbitals.

Question 14

Orbitals

Answer 14

Orbitals are found in subshells. Each orbital can hold 2 electrons. Each subshell has a different amount of orbitals.

Question 15

Which is bigger, the anion of an atom or the neutral atom itself?

Answer 15

The anion of a given atom has a larger atomic radius than the neutral state of the atom. This is because anions have additional electrons, thus lowering effective nuclear charge.

Question 16

Effective Nuclear Charge/Core charge

Answer 16

Effective nuclear charge = Atomic number - electrons in filled shells.
expression of the attractive force experienced by the valence electrons

Question 17

Flaws of John Dalton’s Atomic Theory

Answer 17

Atoms can actually be divided into subatomic particles. Atoms can have different masses (isotopes)
Compounds can be stable in ratios other than a 1:1 ratio.