Presentation on theme: "Bellwork: Copy 1 slide Periodic Table Facts. Atomic number: The atomic number is the number of protons. This number also identifies the element. If the."— Presentation transcript:
Bellwork: Copy 1 slide Periodic Table Facts. Atomic number: The atomic number is the number of protons. This number also identifies the element. If the number of protons change, then the atomic number changes, so the element will become a different element. E.G. Adding a proton to Hydrogen will turn it into Helium because the atomic number will go from 1 to 2.
Bellwork: Copy 1 slide Periodic Table Facts (cont.) Atomic mass: Remember, electrons hardly have any mass so they are basically disregarded when measuring the mass of an element. However, protons and neutrons each have masses of 1 AMU (atomic mass unit.) So, the number of protons added to the number of neutrons give us the atomic mass of an element. Note: Most atomic masses are not an even number. This is because scientists are reporting the average atomic mass of the element on the periodic table. This implies that sometimes elements have different masses. There will be more to com e on this when we talk about Isotopes.
Bellwork: copy 1 slide. Periodic table continued. Isotopes: Sometimes elements are found in nature with extra neutrons, or not enough neutrons in their nuclei. Such cases are referred to as Isotopes. The different atomic masses caused by the existence of isotopes is why atomic masses are not round numbers on the periodic table. So... If you know the atomic number of an element, as well as the mass, it is easy to calculate the number of neutrons. First, round off the atomic mass, then subtract the number of protons (atomic number). The answer to this will be the number of neutrons present.)
Bellwork: copy 1 slide. Periodic Table facts. Note: An elements properties can be predicted by its location in the periodic table. Periods: Horizontal rows in the periodic table are named periods. From left to right, the properties of elements change in a pattern. There are 7 periods on the modern periodic table. Groups: Vertical columns are referred to as groups. There are 18 columns, so there are 18 groups. E.G. Group 1 is called the Alkali Metal group. All of these react violently with water.
Bellwork: Copy 1 slide. characteristics OF METALS Malleable: the ability of a metal to be formed and moulded into another shape without breaking or snapping. Ductile: the ability of a metal to be stretched out indefinitely. Think of copper being stretched into long wires for use in household electricity. Characteristic Lustre: Metals are usually shiny, some more than others. This is due to the shiny sheet of electrons running between the layers and along the surface.
Characteristics of Metals continued Thermal conductivity: Metals conduct heat very well. You would rather use a wooden spoon to stir hot oil than a copper one. Electrical conductivity: Metals have a tendency to be great conductors of electricity. This rule is almost universal; but there are some exceptions. Cations: All elements form ions; but metals almost always form ions that are positively charged. These are know as Cations.
Bellwork: Copy 1 slide Reactivity: The ease and speed with which element combines, or reacts, with other substances is called reactivity. Corrosion: the deterioration of a metal due to a chemical reaction in the environment. E.G. Iron reacts with oxygen and this is called ‘rust’. Alkali metals: Group 1 of the periodic table. Lithium, sodium, potassium, etc. Highly reactive with water. Alkaline Earth metals: Group 2 in the periodic table. These are hard and dense and have high melting points. Magnesium, calcium, etc.
Bellwork: Copy 2 slide Transition metals. These are the metals in groups 3 through 12. iron, copper, nickel, gold, etc. They are less reactive than groups 1 and 2. E.G. Iron rusting is gradual, but Sodium exploding in water is instantaneous. Nonmetals: Elements that lack most of the properties of a metal. They are usually poor conductors of heat and electricity. Solid nonmetals tend to be dull and brittle as opposed to shiny, malleable and ductile.
Bellwork: Metals in mixed groups or metalloids: On the periodic table, at the border between metals and non-metals, there are some elements that have the properties of metals and non-metals at the same time. Example: Aluminum is lighter than most metals and it is also rather stiff in comparison to other metals like copper which are more maleable. A bicycle made of aluminum is great because it is so light; although it is possible for the frame to crack under stress rather than bend.
Bellwork: Lanthanides and Actinides: The two rows of elements that are separate from the rest are called Lanthanides an Actinides. The top row is called Lanthanides and contains Neodymium used to make accurate laser light for performing surgery. The bottom row is called the Actinide series. Most Actinides are not found in nature and must be fabricated in the lab.
Bellwork: Transuranium Elements: All elements with an atomic number of 95 or higher have to be made in a lab using particle accelerators. In the particle accelerator, scientists crash uranium atoms into each other. This is dangerous and the threat of radioactivity is always present. The result is the creation of new elements with atomic numbers higher than 95 are created. These elements are usually unstable and radioactive; therefore deadly to humans. Plutonium is an example an element created in a particle accelerator using uranium.
Bellwork: Nonmetals lack the physical properties of metals. Most non-metals are brittle which means they will crack and crumble when hit with a hammer. Nonmetals are less dense than metals and, except for Hydrogen all non-metals are on the right side of the periodic table. The chemical properties of non-metals are that they usually gain electrons or share electrons when they react with other metals.
Bellwork: Non-Metal Families The carbon family only contains carbon because carbon is so unique. Carbon is located at the top of group 14 in the periodic table. What makes carbon unique is that it is capable of forming long chains. DNA is an example of long carbon chains. Without this unique property, life could not exist. Just below carbon is silicon in group 14. Silicon is also capable of forming long chains although the conditions on Earth are not right for this.
Bellwork: Non-metal Families (continued). The Nitrogen Family is group 15 of the periodic table but only contains phosphorous located just below it. Bellow that are metalloids and metals, so they are not included. 78% of the Earth’s atmosphere is nitrogen. Nitrogen and phosphorous are used a lot in fertilization of farmland and in the life cycle of bacteria.
Bellwork: Non-metal Families continued. The Oxygen Family is group 16 in the periodic table and contains oxygen, sulfur and selenium. 20% of the air we breathe is oxygen and can be argued to be as important to life on Earth as is carbon. You have smelled sulfur when lighting a match. Sulfur is used to make rubber. Phosphorous is so reactive that it bursts into flames when it comes in contact with air. Phosphorous compounds are used to make things glow in the dark.
Bellwork: The Halogen Family The Halogen Family is group 17 on the periodic table and contains fluorine, chlorine, bromine and iodine. Halogens are highly reactive. Fluorine is the most reactive of all the elements and is toxic to the human body. Chlorine is also toxic and reactive; but can be safely used to kill bacteria in water supplies. Halogen atoms are dangerous but the molecules they form in compounds are quite useful. (ex. NaCl)
Bellwork: The Noble Gasses. The Noble Gasses are located in group 18 of the periodic table. Their valence electron shell is full and satisfied. Therefore, noble gasses rarely give up or receive electrons. Therefore they are usually unable to form compounds. They are often referred to as inert gasses because of their non-reactivity. Helium, neon, argon, krypton, xenon and radon are included in the Noble Gasses group.
Bellwork: Hydrogen Hydrogen is in a group by itself. Sometimes it gives up an electron like alkali metals and sometimes it receives an electron like the halogens. It is highly explosive and these explosions produce no pollution. Therefore, if scientists figure out how to produce hydrogen easily and harness its power, machines can be created that are powerful and pollution free.
Radioactive decay: Sometimes elements exist with differing numbers of neutrons and these are called Isotopes. Much of the time, these Isotopes do not have stable nuclei. These nuclei release fast moving particles and energy. This energy and particle release is actually neutrons decaying away. This phenomena is know as radioactive decay.
Nuclear Fission is the process in which the nucleus of an atom splits apart. Deadly amounts of energy are released as witnessed when the US dropped nuclear fission (atomic) bombs on Hiroshima and Nagasaki in Japan in 1945. Nuclear Fusion is the process in which the nuclei of atoms join together. This can also be very destructive.
Alpha decay: A particle consisting of 2 protons and 2 neutrons is called an alpha particle. Essentially, this is the nucleus of the helium atom. Alpha particles are produced during radioactive decay. Beta particle: In a nuclear process called beta decay, a neutron becomes a proton and an electron. The proton stays in the nucleus but the newly created electron speed away. The electron in this scenario is called a beta particle.