BIO 1.1-1.2

7 Properties of Life

Order, sensitivity, repoduction, growth and development

, regulation, adaptation, energy processing

emergent properties of life

help organisms better adapt to their environments and increase their chances of survival

Theory

a tested and confirmed explanation for observations of phenomena that is supported by long term evidence

science is________, ______ and ______

empirical, observable and falsifiable

Chemistry

the science of how tiny particles combine to form everything

Atoms

the building blocks of molecules

Molecules

combined elements that have a characteristic composition and specific atom arrangements

Elements are unique forms of matter that: (3)

-Have specific chemical properties

-Have specific physical properties

-cannot be broken down by chemical means

Four most common elements:

-Carbon

-Oxygen

-Hydrogen

-Nitrogen

How does a molecule differ from an element?

A molecule is comprised of two or more atoms and can be broken down.

Atom

smallest unit of matter that retains all chemical properties of an element

what’s in the outermost region of the atom?

holds electrons in orbit around the nucleus

what’s in the center of the atom?

protons and neutrons

what is the center of the atom called?

nucleus

Isotope

elements with different number of neutrons

What unit is atomic mass expressed in?

atomic mass units (amu)

What is Carbon’s atomic number?

6

Bohr Model

early model with protons in nucleus and electrons in circular orbits at specific distance from nucleus

Orbits

electron shells or energy levels

Where do electrons usually exist (in respect to the nucleus)?

electrons exist in the lowest available energy shell/closest to the nucleus

In what order do electrons fill orbitals?

electrons fill orbitals closest to the nucleus first

Maximum number of electrons per orbital?

2

Valence shell

outer shell

Filled valence shell=

most stable configuration

Valence electrons

the electrons in the outermost shell

_____ and _____ ____determine how chemical reactions occur

orbitals, electron status

reactants

substances used at the beginning of the reaction

products

substances formed at the end of the reaction

covalent bonds

atoms share electron pairs

ionic bond

result of the transfer of an electron to another atom in order to obtain a full valence shell

hydrogen bond

an electrostatic attraction between a hydrogen atom and an electronegative atom