Chapter 2.1: Atoms, Ions, and Molecules
What kind of charge do electrons have?
negative electric charge
Trace elements are required to _______________
survive
What is a molecule?
A molecule is two or more atoms held together by covalent bonds
When does an atom become an ion?
An atom becomes an ion when its number of electrons changes and it gains an electrical charge.
Why do ions form?
An ion forms because an atom is more stable when its outermost energy level is full; the gain or loss of electrons results in a full outermost energy level.
What is the difference between elements and compounds?
Elements cannot be broken down into simpler means while compounds can be broken down into simpler means
When do ions form?
Ions usually form when electrons are transferred from one atom to another
How do ionic bonds form?
It forms through the electrical force between oppositely charged ions
Why is chromium needed in the human body?
It is needed for your cells to break down sugars for usable energy.
Why is iron needed in the human body?
It is needed to transport oxygen to your blood
What is an atom?
The smallest basic unit of matter
What is a covalent bond?
a bond formed when electrons share one or more pairs of electrons
What is an ion?
an atom that has gained or lost one or more electrons
What is every single thing made of?
atoms
Which elements make up the 96% of the human body?
carbon, hydrogen, oxygen, nitrogen
Water and Carbon dioxide are examples of __________________
compounds
What is one particular type of atom that cannot be broken down into a simpler substance by ordinary chemical means?
element
Electrons move around the nucleus in regions called
energy levels
Atoms are most stable when they have a
full valence ring
An atom with a nearly full outer energy level tends __________________________
gain electrons
What is a compund?
it is a substance made of atoms of different elements bonded together in a certain ratio.
An atom that gains one or more electrons becomes a _________________________
negatively charged ion because it has more electrons than protons.
What kind of charge do neutrons have?
no charge
What do protons and neutrons form?
nucleus
The type of ion that forms depends on the number of electrons in an atom's __________________________________
outer energy level
What kind of charge do protons have?
positive electric charge
An atom that loses one or more electrons becomes a __________________________________
positively charged ion because it has more protons than electrons
The electrons in the atoms of each element determine the _________________ of that element
properties
All atoms of a given element have a specific number of ______________
protons
Atoms consist of three types of smaller particles:
protons, neutrons, electrons
What is an ionic bond?
the attractive force between oppositely charged ions
An atom with few electrons in its outer energy level tends _________________
to lose those electrons
How do covalent bonds form?
when atoms share a pair of electrons
