Elements, Compounds And mixtures

Question 1

Element

Answer 1

simplest type of substance with unique physical & chemical
properties

Question 2

An element consists of how many atoms

Answer 2

One

Question 3

Molecule

Answer 3

structure consisting of ≥ 2 atoms chemically bound together

Question 4

Compound

Answer 4

substance with ≥ 2 elements chemically combined

Question 5

Mixture

Answer 5

group of ≥ 2 elements and/or compounds physically intermingled

Question 6

heterogeneous mixture

Answer 6

has one or more visible boundaries between the components.

Question 7

homogeneous mixture

Answer 7

has no visible boundaries because the components are mixed as individual atoms, ions, and/or molecules

Question 8

homogeneous mixture is also called a

Answer 8

solution

Question 9

Solutions in which water is the solvent are called

Answer 9

aqueous solutions

Question 10

The law of mass conservation

Answer 10

total mass of substances does not change during a chemical reaction.

Question 11

Law of Definite (or Constant) Composition

Answer 11

No matter what the source of a compound, its elements occur in the same proportion by mass.

Question 12

Law of Multiple Proportions

Answer 12

when two elements combine with each other to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.

Question 13

Dalton’s Atomic Theory (1)

Answer 13

All matter consists of atoms; tiny indivisible particles of
an element that cannot be created or destroyed

Question 14

Dalton’s Atomic Theory (2)

Answer 14

Atoms of one element cannot be converted into atoms
of another element.

Question 15

Dalton’s Atomic Theory (3)

Answer 15

Atoms of an element are identical in mass and other
properties and are different from the atoms of any
other elemen

Question 16

Dalton’s Atomic Theory (4)

Answer 16

Compounds result from the chemical combination of a
specific ratio of atoms of different elements.

Question 17

Cathode ray tube experiments

Answer 17

(JJ Thompson): existence of electrons (negatively charged particles in all atoms

Question 18

Rays of positive electricity

Answer 18

(JJ Thompson) existence of positively charged subatomic particles

Question 19

Oil drop experiment

Answer 19

(Milliken) charge on the electron (and electron mass)

Question 20

The atom is an:

Answer 20

electrically neutral, spherical entity
* composed of a + charged central nucleus
* surrounded by one or more - charged e - s
* the atomic nucleus consists of + charge protons & (neutral) neutrons

Question 21

Alpha particle backscattering

Answer 21

(Rutherford) nuclear model of atom

Question 22

Isotopes

Answer 22

atoms of an element with the same number
of protons, but a different number of neutrons

Question 23

Isotopes have the same atomic number, but a

Answer 23

different mass number.

Question 24

The Modern Reassessment of the Atomic Theory

Answer 24

all matter is composed of atoms, atoms of one element cannot be converted into atoms of another element in a
chemical reaction, all atoms of an element have the same number of protons and electrons, which determines the chemical behavior of the element, Compounds are formed by the chemical combination of two or more elements in specific ratios.

Question 25

Periodic law

Answer 25

w hen the elements are arranged in order of increasing atomic number, certain sets of properties recur periodically.

Question 26

alkali metals

Answer 26

+1

Question 27

alkaline earth metals

Answer 27

+2

Question 28

chalcogens

Answer 28

-2

Question 29

halogens

Answer 29

-1

Question 30

Noble gases

Answer 30

0

Question 31

metals (characteristcs)

Answer 31

solids (except Hg), electrically & thermally conductive, ductile and malleable, alkaline oxides, electropositive (+ ions)

Question 32

metalloids (characteristics)

Answer 32

solids, electrically semiconductive, hard, amphoteric oxides, electropositive (+ ions)

Question 33

non-metals:

Answer 33

solids/liquids/gases, generally insulating solids, acidic oxides, electronegative (- ions)

Question 34

Compounds

Answer 34

single substances that form by combination of two or more elements combined in specific ratios by mass (moles)

Question 35

Ionic compounds

Answer 35

metal + non-metal or metal + polyatomic ion)

Question 36

Covalent compounds

Answer 36

non-metal + non-metal or non-metal + metalloid)

Question 37

Molecule

Answer 37

the basic unit of a molecular element or covalent compound, consisting of two or more atoms bonded by the sharing of electrons

Question 38

Ion

Answer 38

a single atom or covalently bonded group of atoms that has an overall electrical charge.

Question 39

Polyatomic ions

Answer 39

consist of ≥ 2 atoms covalently bonded together with a net charge. In many reactions the polyatomic ion remains together as a unit.

Question 40

A chemical formula consists of

Answer 40

element symbols with numerical subscripts.

Question 41

The chemical formula indicates the

Answer 41

type and number of each atom present in the smallest unit of a substance.

Question 42

For all ionic compounds, the name and formula lists the

Answer 42

cation first and the anion second.

Question 43

In a binary ionic compound,

Answer 43

both the cation and the anion are monatomic.

Question 44

The name of the cation is the

Answer 44

same as the name of yhe metal, end in -ium

Question 45

The anion is named by

Answer 45

adding the suffix -ide to the root of the nonmetal name