Chapter 2 Flashcards
All matter is composed of certain basic substances called
Elements
Define element
An element is a substance that can’t be broken down to simpler substances with different properties by ordinary chemical means
How many naturally occurring element exist?
92
What are the primary elements that make earth’s crust?
Oxygen, silicon, Aluminum
What are the main elements making organisms?
Oxygen
Carbon
Hydrogen
Nitrogen
Along with
Sulfur
Phosphorus
What’s an atom?
Smallest part of an atom that displays the properties of that element
Atomic number?
The number of protons in each atom
What’s the mass number of an atom?
The sum of protons and neutrons in the nucleus
Isotop
Atoms of the same element that differ in the number of neutrons
What’s compound?
When atoms of two or more different elements bond together, the product called a compound like H2O
Attraction between negatively and positively ions is called
Ionic bond
What’s covalent bond?
It results when two atoms share electrons in such a way that each atom has a complete out orbital
What’s electronegativity ?
The attraction of an atom for the electrons in a covalent bond is called electronegativity
What creates a polar molecule?
The unequal sharing of electrons in a covalent bond creates polar covalent bond.
What’s the attraction between water molecules called?
Hydrogen bond
What’s a calorie?
Amount of heat energy needed to raise the temperature of 1 gram of water by 1C
Dissolved substances are called….
Solutes
Molecules that can attract water are called…
Hydrophilic
Non-ionized and non-polar molecules, such as oil, that cannot attract water are called….
Hydrophobic
What’s matter?
Anything that takes up space and has mass
…is used to indicate the acidity or basicity of solutions.
pH scale
pH scale ranges from ….to ….
0 to 14
pH below 7 is …
Acidic
A pH above 7 is …
Basic