# Victor 7th Grade Science Structure of Matter

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1. Proton -
A proton is a small positively-charged particle in the nucleus of an atom.
2. Neutron -
A neutron is a small uncharged particle in the nucleus of an atom.
3. Electron -
An electron is  tiny negatively-charged, high energy particle that moves in the space outside the nucleus of an atom.
4. Atomic number -
The atomic number is the number of protons in the nucleus of an atom.
5. Mass number -
• The mass number is the mass of an atom.  The mass of an atom is equal to the weight of its nucleus.
• This is true because electrons have basically no weight.  Therefore, the number of protons plus the number of neutrons gives us the mass of an atom.
6. Atomic weight -
The atomic weight of an element can be found directly on the periodic table.  It is not a whole number because it averages the weights of all the different isotopes of that element.
7. Energy level -
• An energy level represents the most likely location in which an electron can be found.
• Electrons with the lowest energy are found in the level closest to the nucleus.
• Electrons with the most amount of energy are found in the energy level furthest away from the nucleus.
8. Principal Energy Level (PEL) -
In modern atomic theory, electrons are arranged in energy levels, or shells.  Each electron shell has certain properties and can hold only a certain number of electrons.

The first energy level (closest to the nucleus) can hold only 2 electrons.

The second energy level can hold 8 electrons.

The third energy level can also hold 8 electrons.

In general, each shell must have its full number of electrons before a new shell starts.  I there are more electrons than a shell can hold, a new shell starts.

*When deciding where to put electrons in an atom, you must fill the lower energy levels before moving to the higher energy levels.
9. Molecule -
A molecule is a combination of two or more atoms that are bonded together.
10. Atom -
An atom is the smallest particle of an element.
11. Chemical symbol -
A chemical symbol is a one or two-letter symbol that identifies most elements.
12. Chemical formula -
A chemical formula is an expression which states the number and type of atoms present in a molecule of a substance.

• Ex: There are 6 C atoms in 14 H atoms in a hexane molecule of a substance...
• C6H14
13. What is the fingerprint of an atom or what determines the identity of an atom?
The energy levels of an atom are the distinctive property of an atom.  The difference between these levels determines the energy of the light emitted or absorbed.  From one atom to another, there are no same energy difference between two levels so spectral lines are referred to as "atomic fingerprints."

They are as unique as  a fingerprint and can therefore be identified by their special lines.
14. Review the charge, mass, and location of all subatomic particles…..
•                           Charge       Mass      Location
• Protons ( p )         +1        1 amu     Nucleus
• Electrons (e)          -1    1/1836 amu  Outside
•                                                      Nucleus
• Neutrons (n)           0          1 amu    Nucleus
15. Where does most of the mass of the atom come from?
Most of the mass of an atom comes from its nucleus.

*Electrons have almost NO weight.
Protons and neutrons have a lot of mass.
16. Where does most of the volume of the atom come from?
Most of the volume of an atom comes from empty space.

17. Where are metals located on the periodic table?
Metals are located on the left side of the periodic table.
18. Where are non-metals located on the periodic table?
Non-metals are located on the right-side of the periodic table.
19. Where are metalloids located on the periodic table?
Metalloids are located on the zig-zag line on the periodic table.
20. Extremely reactive non-metals are called...
Extremely reactive non-metals are called Halogens.
21. Reactive metals are called...
Reactive metals are called Alkaline Earth Metals.
22. Un-reactive non-metals are called...
Un-reactive non-metals are called Noble Gases.
23. What are extremely reactive metals called?
Extremely reactive metals are called Alkali Metals.
24. Elements that have similar properties are located in the same _________?
Elements that have similar properties are located in the same column.
25. The periodic table is arranged in order of increasing __________?
The periodic table is arranged in order of increasing atomic number.
26. Rutherford's model of the atom showed that most of the volume of the atom is composed of __________?
Rutherford's model of the atom showed that most of the volume of the atom is composed of empty space.
27. The energy levels around the nucleus contain?
The energy levels around the nucleus contain electrons.
28. Which particle includes the other three?

a. atom                c. neutron
b. proton              d. electron
• The atom includes…
• the proton, neutron, and electron.
29. Compared to the whole atom, the nucleus of the atom is….
Compared to the whole atom, the nucleus of the atom is….  Smaller and contains most of the atom's mass.
30. Atoms of the same element that have different numbers of neutrons are called ________?
Atoms of the same element that have different numbers of neutrons are called isotopes.
31. An atom of iron contains 26 protons and 30 neutrons.  The mass or atomic mass of iron is?
An atom of iron contains 26 protons and 30 neutrons.  The mass or atomic mass of iron is 56.

30 + 26 = 56.

*To find the number of neutrons in an atom… subtract the number of protons from the atomic mass.
32. Which particles determine the atomic number of an element?
Only the number of protons determines the atomic number of an element.
33. An atom with 5 protons, 6 neutrons, and 5 electrons has an atomic number of?
An atom with 5 protons, 6 neutrons, and 5 electrons has an atomic number of 5.

The number of protons is 5 so that is where the atomic number comes from.
34. What is the mass number of an atom with 9 protons, 11 neutrons, and 9 electrons?
The mass number of an atom with 9 protons, 11 neutrons, and 9 electrons is 20.

• Mass Number = 20
• Protons         =   9
• Neutrons       = 11
35. An element has an atomic number of 63 and a mass number 155.  How many protons are in the nucleus of the element?
There are 63 protons in the element because the atomic number is also the number of protons in the element.
36. The total number of neutrons ion the nucleus of any atom is equal to the...
Mass number minus the atomic number (or number of protons).
37. The positively charged particle in the nucleus of an atom is a?
The positively-charged particle in the nucleus of an atom is a proton.
38. All atoms of hydrogen are alike in that each atom has the same _________?
All atoms of hydrogen are alike in that each atom has the same number of protons.
39. Compared to the charge and mass of a proton, an electron has?
Compared to the charge and mass of a proton, an electron has an opposite charge and a smaller mass.
40. What is the atomic symbol for goldCompared to the charge and mass of a proton, an electron has?
The atomic symbol for gold is Au.
41. Which of the following atoms has the greatest number of valence electrons?

a. O (Atomic No. 8)         c. C (Atomic No. 6)
b. N (Atomic No. 7)         d. F (Atomic No. 9)
F has 9 protons/electrons so its first shell would contain only 2 electrons and its last shell would contain 7 electrons.
42. The electron configuration of an atom of sulfur is ...

*Remember the Principal Energy Level Rule (PEL)… 2, 8, 8
Since the Atomic Number for Sulfur is 16, its electron configuration would be 2, 8, 6.
43. The total number of electrons in the outer shell of a sodium ion is...
The total number of electrons in the outer shell of a sodium ion is 1.

It's electron configuration would be 2, 8, 1 because its Atomic Number is 11.
44. What are valence electrons?
Valence electrons are those electrons in the outermost (last) energy level.
45. Valence Electrons...
Each group or family of the periodic table has exactly the same number of valence electrons which is why they have similar chemical properties.
46. Valence Electrons

The number of valence electrons is equal to the group number for groups 1 and 2, or to the last digit of a two digit group number.
• For example…
• Group 1 has 1 valence electron; group 16 has 6 valence electrons.
47. What are Group 18 elements called?
Group 18 elements are called Noble Gases.  These elements are un-reactive and do not combine with other elements.
48. Where are protons and neutrons found?
Protons and neutrons are found in the nucleus?
49. Where are elections found?
Electrons are found outside the nucleus in the electron shells or orbitals.
50. Each element has a different number of _________ and therefore, a different atomic number.
Each element has a different number of PROTONS, therefore a different atomic number.
51. Atoms of the same element have the same number of protons but can have a different number of _____________?
Atoms of the same element have the same number of protons but can have a different number of NEUTRONS.
52. Can the exact location of an electron be determined?
No, the exact location of an electron cannot be determined.  The location is based on an estimate.
53. The mass number of an element is equal to the number of _________ and _________ in its nucleus.
The mass number of an element is equal to the number of protons and neutrons in its nucleus.
54. The atomic mass of an element can be found where?
The atomic mass of an element can be found on the periodic table.

The atomic mass of an element is the average of all the naturally occurring isotopes of that element.
55. Layout of the periodic table

Horizontal rows are called?
Horizontal rows are called periods.
56. Layout of the periodic table

Vertical columns are called?
Vertical columns are called groups or families.

• They are similar NOT identical in properties.
• They have different number of energy levels.
• They have the same number of electrons in the last energy level.
57. Who developed the Periodic Table?
The Periodic Table was developed by Dmitri Mendeleev and Henry Mosely.

In the modern periodic table, element are arranged in order of increasing atomic number.
58. Metals and Nonmetals

Elements are classified as metals, nonmetals, and metalloids.
Metals are shiny good conductors of heat and electricity, malleable, ductile, and usually are hard.  They are located on the left side of the periodic table.

Nonmetals are dull, not malleable, not ductile, poor conductors of heat and electricity.  They are located on the right side of the periodic table.

Metalloids have properties of both metals and nonmetals and are located on the zig-zag line on the periodic table.
59. Energy Levels

According to the modern atomic theory, electrons are arranged in energy levels.

An energy level represents the most likely location in which an electron can be found.
Electrons with the lowest energy are found in the energy level closest to the nucleus (First Principal Energy Level (PEL).

Electrons with the most amount of energy are found in the energy level further away from the nucleus.
60. Energy Levels

An energy level can only hold a certain number of electrons.
The first energy level can only hold 2 electrons.

The second and third energy levels can hold 8 electrons each.
61. What is a metal?
A metal is a shiny element.  It is...

• - a good conductor of heat and electricity
• - malleable (able to be hammered or pressed permanently)
• - ductile (a physical property of a material associated with their ability to be hammered thin or stretched into wire without breaking)
• - (usually) hard
• - they are located on the left side of the periodic table
62. What is a non-metal?
A non-metal is a dull element.  It is...

• - not malleable (cannot be hammered or pressed permanently)
• - not ductile
• - poor conductor of heat and electricity
• - they are located on the right side of the periodic table
63. What is a metalloid?
A metalloid is an element that has a properties of both metals and nonmetals.

- they are located on the zigzag line on the periodic table
64. What does reactivity mean?
Reactivity is a measure of how actively a substance or chemical reacts with another substance or chemical.

In chemistry, the substances that react are called metals.  The most reactive metals are the Alkali Metals (Sodium, Postassium), while the inert gases or Noble Gases (Helium) don't react at all.
 Author: Costi ID: 251972 Card Set: Victor 7th Grade Science Structure of Matter Updated: 2014-10-05 00:27:34 Tags: Subatomic Particles atomic number mass electrons energy levels Folders: Description: Subatomic Particles, atomic number, mass number, atomic mass, electrons, and energy levels Show Answers: