matter is defined as anything that takes up space and has mass. Matter can exist in many forms, rocks, humans, metals, oils and more.
What is matter made of?
matter is made out of elements.
What is an element?
An element is a substance that that connot be broken down to other substances by chemical reactions.
What is a compound? What are some examples of compounds?
A compound is a substance that consist of two or more different elements combined. An example would be NaCl or table salt.
Out of 92 elements only 20-25% are_______ _______ that an organsim needs to live a healthy life and reproduce.
essential elements
What are the four elements that up 96% of living matter?
Oxygen, Carbon, Hydrogen, Nitrogen
What is an atom? What are they composed of?
an atom is the smallest unit of matter that retains the properties of an element. Although they are the smalles an atom is composed of smaller parts called subatomic particles. Neutrons, Protons, and Electrons
What is electrically charged and has one unit of positive charge?
Proton
What is electically charged and has one unit of negative charge?
Electrons
What is electrically neutral in an atom?
Neutrons
What is atomic nucleus? What does it contain?
The atomic nucleus is the center of the atom, here protons and neutrons are packed togethere tightly.
What is unique of an element and is contained in its nuclei?
Protons
Atoms of the same element who have more neutrons are called?
Isotopes
What is a radioactive isotope?
a radioactive isotope is when the nucleus decasy spontanneously, giving out particle and energy. When the decay leads to a change in number of protons it changes the element.
There is a small amunt of naturally accurring ______________. They can be used to trace metabolic process in living things because the body recognizes the element and still uses it.
radioisotopes
what are used to locate cancer using PET scan and use for dating fossils
radioisotopes
What is potentically harmful because they give off radioctivity which can damage cells; nuclear accidents produce the most danger.
radioisotopes
Electrons are organized into energy leels or
"shells"
Electrons further from nucleus have higher
amounts of energy
Each shell can hold a maximum number of electrons
1st Shell___ electrons
2nd Shell____ electrons
3rd Shell ____electrons
2,8,8
Can give energy and move up to next level: needs extra input of energy
Electrons
The number of electrons in the _____________________ affects the reactivity of the atom
outer shell
Electrons in _____________________; most reactive
outer most shell
They determine how many bonds of atoms can form
Valence
Atoms interact by bonding. Goal is to
completly fill the outside electron shell.
When do chemical bonds occur?
when atoms satisfy their need for electrons by gaining, losing, or sharing electons with one another.
what are Covalent bonds?
electrons are shared by atoms
A molecule is formed when?
more than one atom is bonded together.
a compound is ______________________________________________
two or more different kinds of atoms bonded together.
Molecules can be the _______ kinds of atoms.
same or different
The following examples can be described as
B) C: element
H2: molecule
CH4: molecule/ compound
What are Polar Covalent Bonds
the way electrons are shared is not equal.
Ionic bonds __________ electrons from one atom to another atom.
transfer
Cations has______ charge
positive
Anions has a __________ negative charge
negative
Ions held together by attration of _____________ produces _______ structures