In 1808, the basis of our current atomic theory was developed by?
Atoms have been found to be made up of particles called
Two particles in (2 above ) can be found in the
Show the electrical charges for each of the particles
Electrons- negative charge
Protons- positive charge
Neutrons- neutral (no charge)
Explain how these particles relate to the atomic number and the mass number of an element. Protons in an atom gives the element its atomic number
Thetotal sum of protons and neutrons gives the Mass number of anelement.
Explain how an element can have one or more isotopes. If there exists atoms with an equal number of protons but different number neutrons, then they are isotopes of the element.
Indium (In) has two naturally isotopes. In-113 has a mass of 112.9 a.m.u and an abundance of 4.30%. In-115 has a mass of 114.9 a.m.u and an abundance of 95.70%. Using the weighted average mass method, calculate the atomic mass of Indium. (Show all your work.)
Convertingthe percentages to decimal
=0.957 for In-115
Weightedaverage mass of Indium = (abundance of In-113 in decimal × mass ofIn-113) + (abundance of In-115 indecimal × mass of In-115)
=(0.043 × 112.9) + (0.957 × 114.9)
=4.8547 + 109.9593
=114.8 (to four significant figures)
What are the periods of the periodic table list them numerically?
Thehorizontal rows of elements, which have the same number of energyshell.
Theyinclude Period 1, 2, 3,4,5,6, and 7.
What are the Groups of the periodic table, list their names (if any), and list their Group designations.
Groupsare the vertical columns in the table
GroupI- Alkali metals
GroupII- Alkaline earth metals
GroupVIII- Noble gas
Where can the metals be found on the Periodic Table?
Allelements found on the left hand side of group three elements exceptBoron and Hydrogen and going down along the group in a stair wayexcluding Germanium and Antimony are metals
Explain what a metalloid is and provide the chemical symbols for the known metalloids.
Theyare elements with both properties of metals and nonmetals. Thechemical symbols of known metalloids are: B, Si, Ge, As, Sb, Te
What is an electromagnetic spectrum? It is a term used to describe the electromagnetic waves arranged in order of their wavelengths and frequencies
What is the wavelength of visible light in the Electromagnetic spectrum? 400nm-700nm
Show the wave equation in symbols and by names.
Define a photon and give two examples of how they are used. It is a particle of light that has both energy and momentum. It is employed in a photographic film to convert silver iodide to iodine and silver. Photons are also used during photosynthesis
In an atom, the electron are located in various
What is a sub-level and what are the four classes?
Itis where electrons are found within each energy level
Thefour classes of energy level are s, p, d & f
How many electrons can be located in each of the four classes of sublevels?
Scan accommodate a maximum of 2 electrons
Pholds a maximum of 6 electrons
dholds a maximum of 10 electrons
Fholds a maximum of 14 electrons
In what order is each sublevel filled?
Theenergy sub-level close to the nucleus is filled with electrons firstand once it is filled the next energy sub-level is filled. Thisprocess continuesforall the available electrons
List three primary rules an atom’s electrons follow in filling the orbital of its grounds state.
c) Pauli Exclusion Principle
Why can’t there be more than two electrons in a sub-level?
Electronspossess magnetic fields with north-south possible orientations.Therefore Electrons can reside in one orbital if their orientationsare mutually opposed.
Orbital are arranged from 1st to 4th. Energy levels
The third energy level has 2S orbitals,6p orbitals, and 10 d orbitals
The fourth energy level can hold 32 Electrons, and there are 16 orbitals to accommodate them
Explain how the elements’ electron configuration affect the way the periodic table is arranged.
Elementswith which the electrons number in the outermost energy shell isequal belongs to one group. All elements in a given period havesimilar energy shells
Explain how the electrons in their ground state differ from those in an excited state.
Foran electron to be in an excited state, it must absorb energyequivalent to the energy difference of the two states’ difference.
When an excited electron returns to its ground state it
Releasesthe excess energy as a photon which is seen as visible light inemission spectrum
Explain the octet rule in terms of electron orbital’s. Atoms tend to lose or gain electrons so as to have electrons in the outer most energy level equal to that of its nearest noble gas.
Explain the lack of reactivity of the noble gasses regarding their electron orbitals
Theyhave fully filled electron orbital shells that cannot hold any otherelectrons
What is a valence electron
Itis the electron in the outer shell of an atom which, can betransferred or shared during bonding.
What does Lewis symbol represent?
itrepresents the electrons in the valence shell of an atom or ionplaced around the element’s letter symbol by dots
Provide Lewis symbol for K, Al, As, Cs, Ba, C, O, Xe, and I.
How does atomic size change from top to bottom and from left to right of the Periodic Table?
Asone moves down the group the atomic size rises and from left to rightand the atomic size decreases
How does the ionization energy change from top to bottom and from left to right of the Periodic Table? Increases as you move from left to right and decreases down the group
Explain the difference between elements and an ion of an element. An element the simplest form of substance that cannot be made into simpler substances chemically while an ion is an atom that has lost or gained an electron
Why do elements want to bond? Elements bond so as to attain noble gas electron configuration
Chemical l bonds involve the sharing or transfer of electrons
A cation is a positive ion
An anion is a negative ion
What do you need to be careful of when writing formulae for ionic bonded compounds? Arrangement of the elements and the valences of the elements
Write the formulae for the followings compounds
Barium fluoride – BaF2
Potassium Oxide- K2O
Sodium carbide –Na2C2
Francium bromide –FrBr
Copper II oxide – CuO
Calcium hydride- CaH2
Why do group 1A and 1B elements bond so easily with group 7A elements?
Group1A and 1B elements want to lose 1 electron to attain the noble gaselectron configuration on the other hand group 7A are ‘hungry’for one electron to become stable in the outermost energy shell hencethey bond easily
Explain the mechanism involved in forming an ionic bond. An ionic bond is formed when an electron moves from metallic element to nonmetallic element. When an element loses an electron, it becomes positively charged, and if it gains electrons it becomes positively charged. In an ionic bond, the two oppositely charged ions are held together by electrostatic attraction.
Which types of bonds are most prevalent in nature?
Non-polar covalent bonds share electrons true
An example of a molecule with non-polar covalent bonds is Hydrogen molecule
polar covalent bonds share electrons Yes
An example of a molecule with polar covalent bonds Water molecule
Coordinate covalent bonds share electrons true
Polyatomic ions usually have a) covalent bonds, but form ionic bonds with other ions.
Write formulae for
Beryllium chlorite Be(ClO3)2
Lithium carbonate– Li2CO3
Potassium tartrate – K2C4H4O6
Ammonium phosphate – (NH4)3 PO4
Nickel II thiocyanate – Ni(SCN)2Zinc hexacyanoferrate– Zn2[Fe(CN)6]
Substances with ionic bonds can conduct electricity when molten Or dissolved in water
Elements with metallic bonds can conduct electricity because they have free electrons
The high concentration of positive charge in a hydrogen bond causes the more denser substance to form.
What are dipoles? They are molecules that posses different charges at their end
A ‘’sea’’ of electrons describes the valence electrons of metallic elements
In the space below, draw and fully label a cross-sectional view of a quantum-mechanical
Modelof the atom. Show where the protons, neutrons, electrons, and nucleusare located
orbitals where electrons are found
Nucleuswhere protons and
e e e
P & N
Protonsand Neutrons Nucleus