Periodic Table Part 2 Name_______________________________ Period:________ 4 Learning Objective Using the terms answer the following questions regarding global winds Terms Equator Polar Easterlies Westerlies Tradewinds Doldrums Heated area Coriolis Effect up Air Pressure (high, low) Earth’s rotation Air currents between 0 and 30 latitude are called ___________________ Air current that brings the weather to North America and Canada between 30 and 60 degrees latitude is called _________________________________. Air currents between 60 and 90 degrees latitude are called ____________________ Right near the equator is a windless area called the ___________________________ Zero degrees latitude is called the ____________________________ What factor has the greatest effect on wind speed______________________. Winds move from ______________________ to ______________________. The deflection of winds in the northern hemisphere to the right is called the __________________ ___________________ and is due to Earth’s ____________________ _________________________ rises and can be pushed up and forced ______by cold air. Periodic Table Horizontal rows are called _______________ Numbered ____ Vertical columns are called _____________ Numbered _____ How is the periodic table Element Entry Identification organized?____________________________. Then after the primary organization the periodic table is organized by _______________________________ What is the Atomic Number? 1 ISOTOPES All atoms of any given element have the same numbers of protons (atomic number = Z) in their nucleus. Atoms are identified based on the number protons in the nucleus. The Periodic Table is organized in order of increasing atomic number and chemical reactivities. However, atoms of the same element may have different numbers of neutrons and thus different weights (Mass number = A). The mass number is the total number of protons and neutron in the nucleus. Atoms are said to be isotopes if they are of the same element but they have different masses (weights) due to different numbers of neutrons. C-l2 and C-14 are isotopes. Since both are elemental carbon atoms they have the same number of protons: 6. (The atomic number of carbon is 6.) All elements of carbon have six protons. Atoms of C-l2, like any carbon atoms must have 6 protons. In order for these atoms to have a mass number of 12 they must also contain 6 neutrons (6 protons + 6 neutrons). Atoms of C-14 must also have 6 protons (all carbon atoms do). However, in order for these atoms to have a mass of 14 they must contain _____ protons + ______ neutrons. Generally, isotopes of an element behave identically in terms of how they react with other chemicals. The only difference is in their weights. Isotopes are not present in the same proportion in nature, that is some isotopes are more common than others. Their difference in weight makes they very useful when doing things like medical tests looking how the body responds because an uncommon isotope can be tracked. ISOTOPIC NOTATION Another way of showing isotopes is where X is some element’s symbol, A is the elements mass number and Z is the elements atomic number. Mass Number = Protons +Neutrons Krypton Example How many protons _________ What is the atomic number _____ What is the mass number _____ What is the number of neutrons _____ Hydrogen Isotopes There are three isotopes of hydrogen that all differ by the number of neutrons since all hydrogens have the same number of protons. NORMAL HYDROGEN H-l Most hydrogen atoms consist of just a single proton and an electron... no neutrons; thus H-1 has a mass of 1amu or a mole of H-1 has a mass of 1 gram. About 99.98% of all hydrogen atoms are normal hydrogen; (sometimes called protium). HEAVY HYDROGEN H-2 Sometimes called deuterium. These atoms are twice as heavy as “normal” hydrogen atoms because they contain a neutron in addition to the proton in normal H. TRITIUM H-3 These atoms contain a proton and two neutrons. Draw diagrams showing normal hydrogen, deuterium and tritium label protons (+), neutrons (0) and electrons (-) indicating their respective charges. Normal Hydrogen Deuterium Tritium 2 Complete the Isotope Table to identify the number of subatomic particles atomic mass # of # of # of Isotope name # # protons neutrons electrons uranium-235 uranium-238 131 127 53 Figure out the element from subatomic clues and practice writing isotopic notations ISOTOPE NUMBER NUMBER MASS Average OF OF NUMBER Atomic PROTONS NEUTRONS Mass Cadmium-116 49 113 45 103 197Au Xenon-136 40 71 106 180 33 42 Mercury-204 3H Calculation Space 3 Relative Atomic Mass Describe the masses of protons and neutrons in comparison to electrons ___________________________________________________________________________________ ___________________________________________________________________________________ ___________________________________________________________________________________ ___________________________________________________________________________________ Reactivity relates to electrons Representative Elements Name of Group Group Example Number of Valence Lewis Dot Structure of Group # (symbol) Electrons Valence Electrons alkali metals alkaline earth metals Boron group Carbon group Nitrogen Group Oxygen Group Chacagon halogens noble gases Atoms, tend to take on the lowest-energy, most stable configuration they can. This is why the electron shells of an atom are filled from the inside out, with electrons filling up the low-energy shells closer to the nucleus before they move into the higher-energy shells further out. The number of electrons in the outermost shell of a particular atom determines its reactivity, or tendency to form chemical bonds with other atoms. This outermost shell is known as the valence shell, and the electrons found in it are called valence electrons. In general, atoms are most stable, least reactive, when their outermost electron shell is full. Many of the elements need eight electrons in their outermost shell in order to be stable, and this rule of thumb is known as the octet rule. 4 The structure of the atom - How to draw the Bohr atomic models Atoms are composed of three basic subatomic particles: protons, neutrons, and electrons. In 1913, Niels Bohr came up with a new atomic model. Protons with positive charge and neutrons with neutral charge are located in the nucleus of the atom in the center. Strong nuclear forces hold them together. Electrons orbit around the nucleus on fixed distances called shells. Electrons are negative First shell (the closest to the nucleus) can hold up to two electrons, second eight electrons, third 18, fourth 32. The last 2 things to remember is that electrons will fill the closest to the nucleus shells first and electrons are much smaller compared to protons and neutrons. How to determine the number of protons, neutrons, and electrons in neutral atom • The number of protons in the nucleus of the atom is equal to the atomic number (Z). • The number of electrons in a neutral atom is equal to the number of protons. • The mass number (A) of the atom is equal to the sum of the number of protons and neutrons in the nucleus. To find number of neutrons simply subtract number of protons from the mass number How to find the number of shells? Simply take a look at the period number - it is the number of the shell in given atom. Lithium can be found in the second period so electrons will be placed on two shells Bohr’s atomic model Finally Bohr’s atomic model of lithium will look like this: Figure 1 Orbital How many total electrons First closest to nucleus n=1 Second orbital n=2 Third orbital n=3 Exercise Now it’s your turn: Try to find the number of protons, neutrons and electrons and draw the Bohr’s atomic models for given elements (use periodic table): Aluminum -27 6 9 10 12 4 5 5 For each element, write the total number of electrons on the line. Then color the correct number of electrons for each orbit. Remember, fill the orbit closest to the nucleus first, but never exceed the number each orbit can hold. Check the Periodic Table to find out how many electrons each element actually has. Sodium (Na)__________ Potassium (K)________ Helium (He)_______ Carbon (C) ________ Nitrogen (N) _______ Oxygen (O) _____ Chlorine (Cl)_________ Phosphorus (P)____________ Sulfur (S)_________ 6 Summary 1. How many electrons can each level hold ? 1st _____ 2nd______ 3rd ______ 2. What term is used for the lelectrons in the outermost shell or ender level?____________________ 3. Scientists use two types of diagrams to show the electron confiruration for atoms. Using the Periodic Table complete the following diagrams showing a Bohr Model and a Lewis Structure Bohr Model Lewis Dot Structure All Electrons (valence electrons) Sulfur Atomic Number = 16 Mass Number = 32 Protons = Neutrons = Electrons = Draw the Bohr Model and Lewis Dot structures for the following elements Which elements had a filled outermost shell_____________________________________________ Which element would be most likely to lose electrons in a chemical bond_____________________ Which element would be most likely to gain electrons in a chemical bond Which elements are not likely to bond with other elements? 7 1. Chemical compounds are formed when atoms are bonded together Breaking a chemical bond is an endothermic process. Forming a chemical bond is an exothermic process. Compounds have less potential energy than the individual atoms they are formed from. 2. Two major categories of compounds are ionic and molecular (covalent) compounds. 3. Compounds can be differentiated by their chemical and physical properties. Ionic substances have high melting and boiling points, form crystals, dissolve in water (dissociation), and conduct electricity in solution (aqueous) and as a liquid, not as a solid. Covalent or molecular substances have lower melting and boiling points, do not conduct electricity. Polar substances are dissolved only by another polar substance (water soluble). Non-polar substances are dissolved only by other non-polar substances (oil soluble). Metallic compounds have high melting and boiling points and conduct heat and electricity as a solid or liquid or aqueous.