Elements, Isotopes, and Ions-- How Atoms Differ (Atomic Number and the…
Elements, Isotopes, and Ions-- How Atoms Differ
Different Elements-- Different number of Protons
Matter used to be thought of as cobonations of 4 differenat elements
Element- A pure substance made of atoms that all have the same number of protons.
Atomic Numbers- The number of protons in the atom of an element.
Atomic Number and the Periodic Tables
The elements are arranged horizontally in order of increasing atomic numbers
The elements are also arranged vertically in groups similar properties
Light Blue elements= Metals Yellow= Nonmetals
In almost all Periodic Tables each elements has a...
Isotopes-- Different Numbers of Neutrons
Protons, Neutrons, and Mass Number
Mass Number- the sum of the number of protons and neutrons the atom
Number of neutrons = mass number - number of protons
All atoms of the same element act the same chemically because they have the same number of electrons.
Isotopes- Atoms of the same element that contain different numbers of neutrons
The atoms of the same element can have the same mass number
All the atoms of a particular element have the same atomic number
Average Atomic Mass- An element is the weighted average mass of the mixture.
if you add the number of protons and neutrons you get the mass number.
Isotopes of Hydrogen
Atomic number is 1
Hydrogen has one proton .
Protium has no neutrons and is one hydrogen isotope
Deuterium is made of o proton and one neutron. AND is made of two Hydrogen isotopes
Radioactive isotopes have unstable nuclei that break down and release particles, radiation, and energy.
in hospitals and clinics they use radioactive isotopes to diagnose and treat many medical conditions.
Ions-- Gaining or Losing Electrons
Ions- an atom that is no longer neutral because it has gained or lost electons
When an atom is no longer neutral it becomes a ion.
This happens when it either gains or loses protons or electrons.
Positive Ions-- Losing Electrons
When an atom loses an electron it has more protons the electrons
A positive ion is represented by a (+ sign)
H+= Hydrogen ion
2 electrons= Ca^2
Electrons do not move in circular orbits
Group 1 on the table can easily lose one electron to form positive ions
Group 2 can easily lose 2 electons
Negative Ions-- Gaining Electrons
When an atom gains an electron, it forms an ion with a negative charge.
Group 17 easily gain 1 electron
the sign used is (-)
Group 16 can gain 2 electrons to form ions with a -2 charges, o^2 and s^-2
Positive and negative ions attract each other because of their opposite charges
This is how compounds are formed