Properties of elements and chemical bonds

Question 1

What is the periodic table?

Answer 1

Tabular arrangement of the elements in order of
increasing atomic number
Elements having similar chemical properties are positioned in vertical columns

Question 2

What are periods?

Answer 2

Horizontal rows of elements

Question 3

What are groups?

Answer 3

Vertical columns of elements that have similar
chemical properties

Question 4

What are the Groups with non-numerical names

Answer 4

• Alkali metal (IA)
• Alkaline earth metal (IIA)
• Halogen (VIIA)
• Noble gas (VIIIA)

Question 5

What are the major elements in the human body?

Answer 5

Hydrogen, carbon, nitrogen and oxygen

Question 6

what are the macrominerals in the human body?

Answer 6

Na, Mg, K, Ca, P, S, Cl

Question 7

What are the microminerals (trace minerals) in the human body?

Answer 7

V, Cr, Mn, Fe, Co, Cu, Zn, Si, As, Se, I, Mo

Question 8

What are the classifications of non metals?

Answer 8

• No metallic luster
• Poor electrical conductivity
• good heat insulators
• brittle and nonmalleable

Question 9

What are the classifications metals?

Answer 9

• Metallic grey or silver luster.
• high electrical and thermal conductivity
• Malleable and ductile.

Question 10

What are Metalloids?

Answer 10

• They have some of the properties of metals and some of nonmetals
• Six elements are classified as metalloids: boron, silicon,
  germanium, arsenic, antimony, and tellurium.

Question 11

What are the 4 classification by electronic properties?

Answer 11

Representative elements
noble-gas elements
transition elements
Inner transition elements.

Question 12

What is an electron shell

Answer 12

Region of space around a nucleus that contains electrons
that:
* Have approximately the same energy
* Spend most of their time approximately the same distance
from the nucleus
* Electrons that occupy the first electron shell are closer to
the nucleus and have a lower energy than electrons in the
second electron shell

Question 13

What is a chemical bond? and what are the types?

Answer 13

Attractive force that holds two atoms together in a more
complex unit.
Formed as a result of interactions between electrons found
in the combining atoms.
* Ionic bonds
* Covalent bonds
- Polar covalent bonds
- Non polar covalent bonds

Question 14

What is an Ionic bond?

Answer 14

Formed through the transfer of one or more electrons
from one atom or group of atoms to another atom or
group of atoms
Ionic compound: Compounds in which ionic bonds are
present

Question 15

What is a covalent bond?

Answer 15

Formed through the sharing of one or more pairs of electrons
between two atoms.
There are two types of covalent bonds:
* Polar covalent bonds- non equal sharing of electrons
* Non polar covalent bonds- equal sharing of electrons

Question 16

Important Generalizations About Valence Electrons.

Answer 16

1. Representative elements in the same group have the same
   number of valence electrons
2. The number of valence electrons for representative elements is the
   same as the Roman numeral periodic-table group number
3. The maximum number of valence electrons for any element is
   eight

Question 18

What are lewis symbols?

Answer 18

are electron dot symbols, representing the
number of valence electrons in an atom
a convenient way to represent the valence electrons, which are shown
as dots placed around the symbol for the element

Question 19

What is a valence shell and valence electrons?

Answer 19

Valence Shell: The outer most shell of an atom
Valence electrons: The number of electrons in the outer most
shell

Question 20

Octet rule

Answer 20

Octet rule: The tendency of group 1A-7A elements to react in ways that
achieve an electron configuration of eight valence electrons.

Question 21

What are the guidelines about Electron Loss and Gain by Atoms of
Elements?

Answer 21

-Metal atoms containing one, two, or three valence electrons tend to lose electrons to acquire a noble-gas electron configuration.
* Nonmetal atoms containing five, six, or seven valence electrons tend to gain electrons to acquire a noble-gas electron configuration

Question 22

What is an Ion?

Answer 22

Atom (or group of atoms) that is electrically charged as a result
of the loss or gain of electrons
An atom becomes an ion by gaining or losing
electrons. An atom is neutral (has no charge) Positive and negative ions

Question 23

What is a cation? and examples

Answer 23

Positively charged ion - Atom loses one or more electrons
(Cation) Na+.
Lithium
sodium
potassium
magnesium
have a + on the end of the symbol.

Question 24

What is an anion?

Answer 24

Negatively charged ion - Atom gains one or more electrons
(Anion) Cl-
Nitride
phosphide
oxide
sulfide
Add ide on the end of the element. will have a - on the end of the symbol

Question 25

Transition elements

Answer 25

form more than one type of cations. Different naming system is needed for these cations. A roman number is used in brackets, which shows the charge of the ion

Question 26

Formation of ionic compounds

Answer 26

Ion formation requires the presence of:
A metal that can donate electrons
A nonmetal that can accept electrons
Electrons lost by the metal are the same ones gained by the nonmetal
Positive and negative ions simultaneously formed from an electron transfer attract one another

Question 27

Chemical formulas for ionic compounds

Answer 27

Ionic compounds are always neutral
* No net charge is present
* Ratio in which positive and negative ions combine is the
ratio that achieves charge neutrality for the resulting
compound

Question 28

Writing formulas for ionic compounds

Answer 28

Full name of the metallic element is given first. This is followed by a separate word containing the stem of the nonmetallic element name and the suffix –ide
1. Symbol for the positive ions is always written first
2. Charges on the ions that are present are not shown in the formula
3. Subscripts in the formula give the combining ratio for the ions
NaCl MgO KCl CaS Na2O LiBr

Question 29

what is a covalent bond

Answer 29

A chemical bond resulting from two nuclei attracting the same
shared electrons. Electron sharing produces increased stability
Although all covalent bonds involve sharing of electron pairs,
they differ in the equality of the sharing:

Question 30

Polarity of Covalent Bonds

Answer 30

Sharing of electron pairs,
* Nonpolar covalent bond: Electrons are shared equally.
* Polar covalent bond: Electron sharing is not equal.
* The equality of the sharing depends on the relative electronegativities of the bonded atoms.
In a polar covalent bond:
* the more electronegative atom attracts the shared electrons more
strongly and acquires a partial negative charge
* the less electronegative atom attracts the shared electrons less
strongly and acquires a partial positive charge