Chapter 16
Elements on the left side of the periodic table
alkali earth metals
The sum of the number of protons and neutrons in an atom is the...
atomic mass
A particle that moves around the nucleus is a(n)
electron
The mass of an ____ is about equal to the mass of a proton.
electron
The region around the nucleus occupied by the electrons is called the...
electron cloud
All ----- except mercury are solids at room temperature.
metals
A chemical symbol represents the... of an element.
name
The mass number of an atom is the sum of ____ and ____
protons; neutrons
Elements that have properties of both metals and nonmetals.
semi conductors
Scientists believe that naturally occurring elements are manufactured within
super novas; stars
The periodic table is organized by atomic_____ because it always increases left to right.
weight/mass
How did early chemist like Mendeleev classify the elements?
Atomic mass/weight
Why are noble gases stable?
Full outer shell with 8 electrons
which metalliod is in the fourth period and the same group as carbon?
Germanium
Elements that are gases, or are brittle solids, and are poor conductors at room temperature are?
Metalliods
Each row in the periodic table ends with a____
Noble gas
In general, metals are ____.
good conductors of heat
Metals are good conductors of _________ and _________.
heat; electricity
Atoms of the same element that have different numbers of neutrons are called?
isotopes
Chlorine-35 and chlorine-37 are examples of
isotopes
Noble gases are the ____ reactive elements on the periodic table?
least
Chlorine-35 and chlorine-37 have a different number of?
neutrons
For an atom to be neutral, the number of protons must equal the number of...
neutrons
A very stable electron arrangement in the outer energy level is characteristics of?
noble gases
Most of the mass of an atom is found in its
nucleus
The central core of an atom is called?
nucleus
Every atom of the same element has the same atomic...
number
