The document discusses the components and structure of atoms. It defines elements, molecules, compounds, and mixtures. Atoms consist of subatomic particles including protons, neutrons, and electrons. The number of protons determines the element, while the number of neutrons distinguishes between isotopes of the same element. The periodic table arranges elements based on atomic number and properties. Elements are classified as metals, nonmetals, and metalloids based on their properties. Valence electrons determine an element's chemical properties and reactivity. Atomic size and ionization energy depend on position in the periodic table.

1. Components of Matter
Ivy Joyce A. Buan, RCh, LPT

2. What are the
components of
an atom?

3. •Element is the building block of matter.
It consists of one kind of atom.
•Molecule consists of two or more atoms
chemically bound together.
•Compound a substance composed of
two or more elements that are
chemically combined.
•Mixture is a group of two or more
elements and compounds that are
physically intermingled.

4. Dalton’s Atomic Theory
•All matter consists of an atom.
•Atoms of one element cannot be
converted into atoms of other
elements.
•Atoms of an element differ from the
other elements.
•Compound is a result of a chemical
combination of a specific ratio of atoms
of different elements.

5. The Atom
• An atom consists of a nucleus that contains protons
and neutrons. Wherein, of electrons, are in a large,
empty space around the nucleus.

6. Subatomic Particles
Atoms contain subatomic
particles.
• Protons have a positive (+)
charge.
• Electrons have a negative (–)
charge.
• Like charges repel, and unlike
charges attract.
• Neutrons are neutral.

8. 8
Learning Check
Identify each statement as describing a(n)
1) proton 2) neutron 3) electron
A. __ found outside the nucleus
B. __ has a positive charge
C. __ is neutral
D. __ found in the nucleus

9. 9
Solution
Identify each statement as describing
a(n)
1) proton 2) neutron 3) electron
A. 3 found outside the nucleus
B. 1 has a positive charge
C. 2 is neutral
D. 1, 2 found in the nucleus

10. Atomic Symbols

11. Example: An atom of sodium with atomic
number 11 and a mass number 23 has the
following atomic symbol:

12. State the number of protons,
neutrons, electrons, and names in
each of the following.

13. 13
For an atom, the nuclear symbol gives the
number of
▪protons (p+)
▪neutrons (n)
▪electrons (e–)
8 p+ 15 p+ 30 p+
8 n 16 n 35 n
8 e– 15 e– 30 e–
16
8 O 31
15 P 65
30
Zn

14. How same
element but have
different mass
number formed?

15. Isotopes
•are atoms of the same element
that have different mass
numbers
•have the same number of
protons but different numbers
of neutrons.

16. 16
Naturally occurring carbon consists of three
isotopes, C-12, C-13, and C-14. State the
number of protons, neutrons, and electrons
in each of the following.
protons ______ ______ ______
neutrons ______ ______ ______
electrons ______ ______ ______
Learning Check
12
6
C 13
6 C 14
6 C

17. 17
protons 6 p+ 6 p+ 6 p+
neutrons 6 n 7 n 8 n
electrons 6 e– 6 e– 6 e–
Solution
12
6
C 13
6
C
14
6
C

18. 18
Write the nuclear symbols for atoms
with the following subatomic
particles:
A. 8p+, 8n, 8e– ___________
B. 17p+, 20n, 17e– ___________
C. 47p+, 60n, 47e– ___________
Learning Check

20. 20
A. 8p+, 8n, 8e–
B. 17p+, 20n, 17e–
C. 47p+, 60n, 47e–
Solution
16
8 O
37
17 Cl
107
47 Ag

21. 21
Learning Check
1. Which of the following pairs are isotopes of the same
element?
2. In which of the following pairs do both atoms have
8 neutrons?
A.
B.
C.
12
6 X 15
7 X
12
6 Z 14
6Z
15
7 Z 16
8Z

22. 22
Solution
1. B
Both nuclear symbols represent isotopes of carbon with
six protons each, but one has 6 neutrons and the other
has 8.
2. C
An atom of nitrogen (atomic number 7) and an atom of
oxygen (atomic number 8) each have 8 neutrons.

23. How can you
determine the
mass of an atom?

24. 24
Atomic Mass
The atomic mass of an element
▪is listed below the symbol of each
element on the periodic table
▪gives the mass of an “average” atom
of each element compared to C-12
▪is not the same as the mass number
Na
22.99

25. 25
Some Elements and Their Atomic Mass
Most elements have two or more
isotopes that contribute to the atomic
mass of that element.

26. 26
Using the periodic table, give the atomic mass
of
each element.
A.calcium __________
B. aluminum __________
C. lead __________
D. barium __________
E. iron _________
Learning Check

27. 27
Using the periodic table, give the atomic
mass of
each element.
A.calcium 40.08 amu
B. aluminum 26.98 amu
C. lead 207.2 amu
D. barium 137.3 amu
E. iron 55.85 amu
Solution

28. The Periodic Table of Elements
On the periodic table
• Groups contain elements with similar properties and are
arranged in vertical columns.
• Use numbers 1–18 to identify the columns from left to
right.
• Use the letter A for the representative elements (1A to
8A) and the letter B for the transition elements
• Periods are the horizontal rows of elements.
• Elements in the periodic table is arranged in order of
increasing atomic number as you move from left to right.

32. 32
Alkali Metals
Group 1A(1), the alkali metals,
includes lithium, sodium, and
potassium.

33. 33
Halogens
Group 7A(17), the
halogens, includes
chlorine, bromine,
and iodine.

34. 34
Identify the element described by the following:
A. Group 7A(17), Period 4
1) Br 2) Cl 3) Mn
B. Group 2A(2), Period 3
1) beryllium 2) magnesium 3) boron
C. Group 5A(15), Period 2
1) phosphorus 2) arsenic 3) nitrogen
Learning Check

35. 35
A. Group 7A (17), Period 4
1) Br
B. Group 2A (2), Period 3
2) magnesium
C. Group 5A(15), Period 2
3) nitrogen
Solution

36. 36
Metals, Nonmetals, and Metalloids
The heavy zigzag line
separates metals and
nonmetals.
▪ Metals are located to the
left.
▪ Nonmetals are located to
the right.
▪ Metalloids are located
along the heavy zigzag line
between the metals and
nonmetals.

37. 37
Metals
▪ are shiny and ductile
▪ are good conductors of heat and electricity
Nonmetals
▪ are dull, brittle, and poor conductors of heat and
electricity
▪ are good insulators
Metalloids
▪ are better conductors than nonmetals, but not as good
as metals
▪ are used as semiconductors and insulators
Properties of Metals, Nonmetals, and
Metalloids

38. 38
Comparing a Metal, Metalloid, and
Nonmetal

39. 39
Identify each of the following elements
as:
1) metal 2) nonmetal 3) metalloid
A. sodium ____
B. chlorine ____
C. silicon ____
D. iron ____
E. carbon ____
Learning Check

40. 40
Identify each of the following elements as:
1) metal 2) nonmetal 3) metalloid
A. sodium 1 metal
B. chlorine 2 nonmetal
C. silicon 3 metalloid
D. iron 1 metal
E. carbon 2 nonmetal
Solution

41. 41
Match the elements to the description.
A. Metals in Group 4A(14)
1) Sn, Pb 2) C, Si 3) C, Si, Ge, Sn
B. Nonmetals in Group 5A(15)
1) As, Sb, Bi 2) N, P 3) N, P, As, Sb
C. Metalloids in Group 4A(14)
1) C, Si, Ge, 2) Si, Ge 3) Si, Ge, Sn, Pb
Learning Check

42. 42
Match the elements to the description.
A. Metals in Group 4A (14)
1) Sn, Pb
B. Nonmetals in Group 5A(15)
2) N, P
C. Metalloids in Group 4A(14)
2) Si, Ge
Solution

43. The valence electrons
• determine the chemical properties of the elements
• are the electrons in the outermost, highest energy
level
• are related to the Group number of the element
• All the elements in a group have the same number
of valence electrons.
Example: Phosphorus has 5 valence electrons.
5 valence
electrons
P Group 5A(15) 1s22s22p63s23p3

44. •Example: Elements in Group
2A(2) have two (2) valence
electrons.
• Be 1s22s2
• Mg 1s22s22p63s2
• Ca [Ar]4s2
• Sr [Kr]5s2

45. 45
Periodic Table and
Valence Electrons

46. 46
State the number of valence electrons
for each.
A. O
1) 4 2) 6 3) 8
B. Al
1) 13 2) 3 3) 1
C. Cl
1) 2 2) 5 3) 7
Learning Check

47. 47
State the number of valence electrons
for each.
A. O
2) 6
B. Al
2) 3
C. Cl
3) 7
Solution

48. 48
State the number of valence electrons for
each.
A. Calcium
1) 1 2) 2 3) 3
B. Group 6A (16)
1) 2 2) 4 3) 6
C. Tin
1) 2 2) 4 3) 14
Learning Check

49. 49
State the number of valence
electrons for each.
A. Calcium
2) 2
B. Group 6A (16)
3) 6
C. Tin
2) 4
Solution

50. 50
State the number of valence
electrons for each.
A. 1s22s22p63s23p1
B. 1s22s22p63s2
C. 1s22s22p5
Learning Check

51. 51
State the number of valence
electrons for each.
A. 1s22s22p63s23p1 3
B. 1s22s22p63s2 2
C. 1s22s22p5 7
Solution

52. 52
Atomic Size
▪ is described using the atomic
radius
▪ is the distance from the nucleus to
the valence electrons
▪ increases going down a group
▪ decreases going across a period
from left to right

53. 53
Atomic Size

54. 54
Atomic Radius Within A Group
Atomic
radius
▪increases
going down
a group

56. 56
Learning Check
Select the element in each pair with
the larger atomic
radius.
A. Li or K
B. K or Br
C. P or Cl

57. 57
Solution
Select the element in each
pair with the larger
atomic radius.
A. K is larger than Li
B. K is larger than Br
C. P is larger than Cl

58. SP 1. Arrange each set in
order of increasing atomic
size.
A.Rb, K, Cs
B.C, O, Be
C.Cl, K, S
D.Mg, K, Ca

59. 59
Ionization Energy
▪is the energy it takes to
remove a valence electron
from an atom in the gaseous
state
Na(g) + Energy (ionization) Na+(g) + e–

60. •Increases from bottom to up of the
group and increases across the
period.
•Successive ionization energy of a
given elements increases because
each electron is pulled away from
an ion with progressively higher
positive charge.

63. •SP 2. Arrange each set of
atoms in order of increasing
ionization energy.
A. Sr, Ca, Ba
B. N, B, Ne
C. Br, Rb, Se
D. As, Sb, Sn

64. 64
Learning Check
Select the element in each
pair with the higher
ionization energy.
A. Li or K
B. K or Br
C. P or Cl

65. 65
Solution
Select the element in each pair
with the higher
ionization energy.
A. Li is higher than K
B. Br is higher than K
C. Cl is higher than P

66. Electron Affinity (EA) is the energy change in
the addition of 1 mol of electron to 1 mol of
gaseous atoms or ions.