STAAR 8th Grade Science-Chemistry Review tutorial 1

Explain how an element in period 2 compares to an element in period 3.

An element in period 3 would have 1 more electron shell than an element in period 2

Who developed the first periodic table?

Dimitri Mendeleev

Which atomic particle is the smallest?

Electrons- they are so small, they do not count in the mass of the atom.

What are the horizontal rows on the periodic table called?

Periods- rows 1-7; go across the periodic table

What are the charges of each subatomic particle?

Protons + Neutrons 0 Electrons -

Where are each of the particles located?

Protons and Neutrons are located in the Nucleus and Electrons are located in the electron cloud;

What are the three subatomic particles found inside an atom?

Protons, Neutrons, and Electrons

Explain the reactivity of elements in the same group or family.

Reactivity is similar due to the same number of valence electrons

How do you find the number of neutrons in an atom?

Round the Atomic Mass to make it the Mass Number them subtract the Atomic Number. M-A=N

Explain how an atom's overall electric charge is neutral.

Same number of protons and electrons- the charge on one proton is equal to the charge on one electron so the particles cancel each other out

Explain the difference in the reactivity of Sodium & Magnesium.

Sodium Na is more reactive than Mg because it has only one valence electron and Mg has two

Explain how a nonmetal in period 4 compares to a metal in period 4.

The nonmetal will have more valence electrons- 6,7 or 8; metals only 1 or 2

How is the periodic table arranged?

by increasing atomic number

negative (-)

charge of electrons

neutral (0)

charge of neutrons

positive (+)

charge of protons

valence electrons

electrons that are found in the outermost occupied shell of an atom.

An ____ is the substance that cannot be broken down into other substances by chemical or physical means.

element

What state of matter are most of the nonmetals?

gases

What are some common properties of metals?

good heat and electricity conductors, ductile, malleable, mostly solids, give up electrons ; left of the periodic table

(it has) equal numbers of protons and electrons

how an atom's overall charge is neutral

atom

smallest particle of an element

The electrons in the outermost occupied shell and involved in chemical reactions are called ____.

valence electrons

Metalloid names:

-Boron -Silicon -Germanium -Arsenic -Atimony -Terellium

How would you describe the structure of an atom?

A tiny central positively charged core of Protons and Neutrons called the Nucleus surrounded by one or more Electrons moving rapidly

What are the vertical columns of the periodic table called?

Groups or families- 18 vertical columns; only the "A" groups follow the valence electron rule

What do you know about an element from its number of valence electrons?

How reactive it is.

Where is most of the volume in an atom?

In the electron cloud- mostly empty space

Explain how the reactivity changes across the periodic table in the METALS & in the NONMETALS.

METALS- it decreases as you move left to right; Group 1 is the most reactive of the metals NONMETALS- reactivity increases as you move left to right from groups 13-17; Group 18 nonreactive; Group 17 most reactive of the nonmetals

An atom's ___ is equal to the number of protons plus the number of neutrons.

Mass number

What is special about the Noble gases and where are they located on the periodic table?

Noble gases have full electron shells and are the least reactive; right side of the periodic table in group 18

What does the number of each period (row) represent?

Number of energy levels (electron shells; orbitals)

Where is most of the mass?

The nucleus- this is where the protons and neutrons are located.

1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A

The numbers on the periodic table that tell you how many valence electrons you have.( Don't use the numbers with B's after them to tell you the valence electrons)

What is the mass number of an atom?

The rounded atomic mass, or the P +N

Why are metalloids categorized by themselves?

They have properties of metals and nonmetals

electron cloud

location of electrons

nucleus

location of protons and neutrons

(group) 1

most reactive group of metals with 1 valence electron

(group) 17

most reactive group of nonmetals with 7 valence electrons