Science Chapter 18
One proton and one electron are ............ to each element as you go across the periodic table.
added
The sum of the number of protons and neutrons in an atom is the ....................
atomic mass
Why are noble gases stable?
b/c all of their energy leveels are full and complete.
Moving from left to right in a row of the periodic table, metallic properties .............
decrease
In 1926, scientist developed the .............. model of the atom that is in use today.
electron cloud
The region around the nucleus occupied by the electrons is called the ...............
electron cloud
The sum of the number of protons and neutrons in an atom is the ..................
mass number
The atomic number of an element is determined by it's number of ...............
protons
The atomic number of an element is determined by its number of ................
protons
Scientists believe that naturally occurring elements are manufactured within ..............
stars
Where are the groups located at on the table?
up and down
Each inner energy level of an atom has a maximum number of ............... it can hold. A: electrons C: quarks B: neutrons D: protons
A. Electrons
Atoms of the same element with different numbers of neutrons are called ............. A: isotopes C: metalliods B: metals D: radioactive elements
A. Isotopes
A chemical symbol represents the ............. of an element. A: name C: group B: reaction D: structure
A. Name
A particle that moves around the nucleus is a(n) .................... A: electron C: neutron B: proton D: quark
A. electron
A ............... is used to accelerate protons in the study of subatomic particles. A: tevatron C: technology B: temanite D: television
A. tevatron
A chemical symbol represents the ............ of an element. A: name C: group B: reaction D: structure
A: name
Group of elements that are gases, are brittle, and are poor conductors at room temperature are ............... A: metals C: metalliods B: nonmetals D: isotopes
B. Nonmetals
particles of matter that make up protons and neutrons are ......... A: electrons C: quarks B: isotopes D: atoms
C: quarks
The symbol for chlorine is ..............
Cl
A certain atom has 45 protons, 45 electrons, and 58 neutrons. Its mass number is .................. A: 45 C: 90 B: 58 D: 103
D. 103
A certain atom has 26 protons, 26 electrons and 30 neutrons. Its mass number is .................... A: 26 C: 52 B: 30 D: 56
D. 56
Dot diagrams are used to represent ........... A: atomic numbers C: isotopes B: atomic mass D: outer level electrons
D. Outer level electrons
Horizontal rows of the periodic table are called ................... A: clusters C: groups B: families D: periods
D. periods
Who created the modern periodic table?
Henry G.J. Moseley
How many periods are on the periodic table?
18
The maximum number of electrons in the third energy level of an atom is ...............
18
So far, scientist have confirmed the existence of ........ different quarks.
6
how many groups are on the periodic table?
7
The maximun number of electrons in the second energy level of an atom is ...........
8
Metals are ................ conductors of heat and electricity.
good
Elements arranged in vertical columns in the periodic table are called ...................
groups
The symbol for .................. is Fe.
iron
Where are the periods located on the table?
left and right
The mass of an ........... is about equal to the mass of a proton.
neutron
Two isotopes of carbon-12 and carbon-14. These isotopes differ from one another by two ..........
neutrons
A very stable electon arrangement in the outer energy level is a characteristic of .................
noble gases
Non-metals are .............. conductors of heat and electricity.
not good
The central core of an atom is called the ...........
nucleus
The chart showing the classifications of elements according to their properties and increasing atomic numbers is called the ..................................
periodic table
