Laminate each page and cut out the cards. About this Lessonīoth this lesson and Lesson 4.3-The Periodic Table and Energy Level Models both use the atom description cards. The activity sheet will serve as the “Evaluate” component of each 5-E lesson plan.
Evaluationĭownload the student activity sheet, and distribute one per student when specified in the activity. They will also be able to explain the meaning of atomic number and atomic mass. Students will identify different atoms by the number of protons in the nucleus and realize that the number of electrons equals the number of protons in a neutral atom. Students will then watch several videos of some interesting chemical reactions involving some of these elements. They will try to correctly match cards with information about an element to each of the first 20 elements. Students will focus on the first 20 elements. They will be introduced to the basic information given for the elements in most periodic tables: the name, symbol, atomic number, and atomic mass for each element. Students will begin to look closely at the periodic table. The atoms in the periodic table are arranged to show characteristics and relationships between atoms and groups of atoms.The atomic mass of an element is the average mass of the different isotopes of the element.Atoms of the same element with different numbers of neutrons are called “isotopes” of that element.Different atoms of the same element can have a different number of neutrons.The number of electrons surrounding the nucleus of an atom is equal to the number of protons in its nucleus.The atomic number of an atom is equal to the number of protons in its nucleus.An element is a substance made up of only one type of atom.The periodic table is a chart containing information about the atoms that make up all matter.How does the reactivity of non–metals change in a period and group?Īns: Reactivity generally represents the property of non-metals which measures its tendency to gain electrons. Predict the position of the element in the periodic table satisfying the electronic configuration $(n-1)$ 11 protons are present which exert higher effective nuclear charge and the tendency of removing an electron is quite difficult as compare to Ne as it has only 10 protons.ġ3. What is the electronic configuration when elements are classified group-wise?Īns: Those elements which are in the same group have the same number of valence electrons and also show similar physical and chemical properties.ġ0. The seventh period is incomplete it starts with francium having atomic number 87 and up to 93 onwards are purely synthetic in nature and are called transuranium elements.Īns: Electronic configuration defines how electrons are distributed into orbitals of an atom.ĩ. The sixth period contains 32 elements starting from caesium and the last one is radon and is said to be the longest period. The fourth and fifth periods both contain 18 elements from potassium to krypton in the fourth and rubidium to xenon in the fifth period these are long periods. The second and third periods both contain 8 elements from lithium to neon in the second period while from sodium to argon in the third period.
In short, give the features of the seven periods.Īns: The first period is said to be the shortest period containing only two elements hydrogen and helium. The elements present in groups 3-12 are called transition elements.ħ. The elements present in groups 1, 2 and 13-17 are called main group elements. Seven horizontal rows are known by the name periods. Their groups are numbered from left to right as 1-18. Give the general characteristics of the long form of the Modern periodic table?Īns: General characteristics of the long form of Periodic table can be discussed as follows: Define and state Mendeleev’s periodic law.Īns: This law states that elements are arranged according to their atomic weight.Ħ. What is the basis of the triad formation of elements?Īns: Triad formation is basically dependent upon the middle element which represents that the atomic weight of the middle one is the half of the other two elements of the triad which are in between these two elements and this relationship is also given by Dobereiner know as the law of triads.Īns: Elements are arranged according to their physical and chemical properties and with the increase in atomic numbers.ĥ. Who was the first scientist to classify elements according to their properties?Īns: In the year 1829, a German scientist named Johann Dobereiner was the first one who classified elements according to their properties.ģ. How many elements are known at present?Īns: At present 114 elements are known to us.Ģ.
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