Chapter 2 Flashcards
Give an example of a trace element that all organisms need
Iron
What 4 elements make up 96% of living matter? And 2 additional
CHONPS Carbon Oxygen Hydrogen Nitrogen Phosphorus Sulfur
Give an example of a trace element that all vertebrates need
Iodine
The mass number of any element is the sum of what two sub particles?
Protons and neutrons
Protons and electrons are always what?
The same amount
How do you find the neutrons?
Subtract the number of protons from the mass
What are isotopes?
It can have the same amount of protons, but different smooth of neutrons, causing a different atomic mass
How many electrons are found in the third valence shell of electrons?
18
When is a covalent bond polar?
A covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive. Example: water
Why are water molecules attracted to eachother?
Hydrogen bonds hold water together. The negative in the O attracted the positive in the H
How many of the 92 elements are essential?
25
An elements properties depend in what?
The structure of its atoms
What are the subatomic particles of an atom?
Proton, electron, neutron
Elements with a full valence shell are ..?
Chemically unreactive
What is the unit to measure mass for atoms and subatomic particles
Dalton
