Chapter 2 Flashcards
(78 cards)
Chemistry
The science that deals with the structure of matter
Composition of matter
Atoms
Atoms
• definition
• what defines
Smallest stable unit of matter
•Types and arrangements of atoms define unique characteristics of matter
Atomic structure
•what does it include
3 subatomic particles (electrons, protons and neutrons)
Electrons
Occupy outer “shells”
Nucleus
• what does it include
• definition
- protons and neutrons
* determines mass of atom
Atomic number
Number of protons in an atom
• Usually atoms contain equal numbers of protons and electrons but not always
Chemical elements
A substance made up of 1 kind of atom
How many elements are there?
92 elements exist in nature
Principle elements of the human body
• 13
- Oxygen (O2)
- Carbon (C)
- Hydrogen (H)
- Nitrogen (N)
- Calcium (Ca)
- Phosphorus (P)
- Potassium (K)
- Sodium (Na)
- Chloride (Cl)
- Magnesium (Mg)
- Sulfur (S)
- Iron (Fe)
- Iodine (I)
Trace elements
- Only present in very small amounts
* 14 trace elements found in the body
Atomic mass
Total number of protons and neutrons in the nucleus of an atom
Isotope
• definition
• two kinds
• example
- Atom whose nuclei contain the same number of protons but differ in the number of neutrons
- stable and radioisotope
- Hydrogen has 3 isotopes
3 isotopes of hydrogen
- H= 1p+1e } stable isotope
- H= 1p + 1n + 1e }stable isotope
- H= 1p + 2n + 1e } radioisotope
Stable isotope
Nucleus of an atom does not emit subatomic particles spontaneously
Radioisotope
Nucleus of an atom emits subatomic particles spontaneously
How is matter combined?
By chemical bonds
How are chemical bonds formed?
Formed from interaction between 2 or more atoms
3 types of chemical bonds
- Ionic
- Covalent
- Hydrogen
Ionic bond
• What are they
• how are they created
- Ions: have unequal numbers of protons and electrons
* Bonds created by electrical attraction between cation and anions
Covalent bonds
• definition
• what forms single, double, or triple bonds
- Bond where 1 or more electrons are shared between atoms
* Depending on the number of electron pairs shared -will form single, double or triple bonds
Hydrogen bonds
- weak attractive forces
- attraction of partially positive charged hydrogen with a partially negative charged atom
- Important for changing the shape of molecules together
Molecule
• Definition
• 6 examples
Any chemical structure held together by covalent bonds • Hydrogen gas (H2) • Oxygen gas (O2) • Water (H2O) • Carbon dioxide (CO2) • DNA • RNA
Compound
• defintion
• 5 examples
- a chemical substance made of atoms of 2 or more different elements regardless of the type of bond joining them
- Sodium chloride (NaCl)
- Water (H2O)
- Carbon dioxide (CO2)
- DNA
- RNA