CHAPTER 12-5 & 6

WHICH SIMPLE ION WOULD EACH OF THE FOLLOWING ELEMENTS BE EXPECTED TO FORM? WHICH NOBLE GAS HAS AN ANALOGOUS ELECTRON CONFIGURATION TO EACH OF THE IONS? A. BROMINE, Z=35 B .CESIUM, Z=55 C. PHOSPHORUS, Z=15 D.SULFUR, Z=16

A. Br-[Kr] B. Cs+ [Xe] C. P3- [Ar] D. S2- [Ar]

EACH OF THE FOLLOWING DIATOMIC MOLECULES, WHICH END OF THE MOLECULE IS POSITIVE RELATIVE TO THE OTHER END? A. HYDROGEN FLUORIDE, HF B. CHLORINE MONOFLUORIDE, CF C. IODINE MONOCHLORIDE, ICI

A. Hydrogen B. Chlorine C. Iodine

IN A BOND BETWEEN FLUORINE AND IODINE, WHICH HAS MORE ATTRACTION FOR AN ELECTRON? WHY?

in the bond between fluorine and iodine, the atom that has more attraction for an electron is fluorine. Fluorine pulls the electron belonging to iodine. The atomic radius of iodine 198 pm. Electronegativity iodine - 1.9 and fluorine - 4.0.

How a Hypothesis can become a theory? Can a theory become a law?

A theory ( model) is a set of tested hypotheses that gives an overall explanation of some part of nature. A theory is an interpretation. We continue doing experiments, we make new observations to see whether the results bear out this predictions.

WHY DO ATOMS FORM BONDS WITH ONE ANOTHER? WHAT CAN MAKE A MOLECULE FAVORED COMPARED WITH THE IONE ATOMS?

Atoms form bonds to function as a unit and be more stable.. Molecules have more stability so they are more favored. It is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electrostatic force of attraction between opposite charges, wither between electrons and nuclei, or as the result of a dipole attraction.

THE METALLIC ELEMENTS LOSE ELECTRONS WHEN REACTING, AND THE RESULTING POSITIVE IONS HAVE AN ELECTRON CONFIGURATION ANALOGOUS TO THE --------------------------NOBLE GAS ELEMENT.

PRECEDING

EXPLAIN EXPLAIN HOW YOU CAN USE THE PERIODIC TABLE TO PREDICT THE FORMULA OF COMPOUNDS.

THE METHOD BY WHICH THE PERIODIC TABLE IS USED TO PREDICT THE FORMULA OF THE COMPOUNDS IS TO BE STATED. THE ROWS OF THE PERIODIC TABLE ARE KNOWN AS GROUPS. THE ELEMENTS IN THE SAME GROUP HAVE THE SAME GENERAL ELECTRONIC CONFIGURATION. THE ELECTRONIC CONFIGURATION OF THE ELEMENTS HELPS TO KNOW THE NUMBER OF VALENCE SHELL ELECTDRONS. THESE VALENCE ELECTRONS ARE USED TO MAKE BONDS BETWEEN TWO ATOMS BY SHARING. THE FORMATION OF THE COMPOUND IS BASED ON THE CONSIDERATION THAT ATOMS MUIST ACHIEVE THE NOBLE GAS CONFIGURATION BY SHARING, GAINING OR LOSING THE VALENCE ELECTRONS.

WHAT IS MEANT BY THE TERM ELECTRONEGATIVITY? WHAT ARE THE TRENDS ACROSS AND DOWN THE PERIODIC TABLE FOR ELECTRONEGATIVITY? EXPLAIN THEM, AND DESCRIBE HOW THEY ARE CONSISTENT WITH TRENDS OF IONIZATION ENERGY AND ATOMIC RADII

The unequal sharing of electrons between two atoms is described by a property called electronegativity: the relative ability of an atom in a molecule to attract shared electrons to itself. Electronegativity generally INCREASES going from LEFT TO RIGHT across a period and DECREASES going DOWN a group for the representative elements. The higher the atom's electronegativity value, the closer the shared electrons tend to be to that atom when it forms a bond. Therefore the closer the electron to the nuclear the higher the attraction force, and thus the higher the energy required to overcome this attraction and remove the electron. Therefore the smaller the radius the higher the ionization energy, and the bigger the radius the lower the energy need. Electronegativity is a measure of the attraction of an atom for the electrons in a chemical bond. The higher the electronegativity of an atom, the greater its attraction for bonding electrons. The smaller the atom, the larger the nuclei attraction

THE MOLECULES NH, AND BF, HAVE THE SAME GENERAL FORMULA (AB3) BUT DIFFERENT SHAPES. A. FIND THE SHAPE OF EACH OF THE ABOVE MOLECULES. B. PROVIDE MORE EXAMPLES OF REAL MOLECULES THAT HAVE THE SAME GENERAL FORMULA BUT DIFFERENT SHAPES.

to work out the shape of a molecule you need to work out how many bonds, and how many lone pairs of electrons the central atom has. we will start with NH3. nitrogen has 5 valence (reacting) electrons, and each hydrogen will form a single covalent bond with the nitrogen. 3bonding pairs + 1 lone pair = 4 bonds total because it has 4 bonds it forms a tetrahedral shape, with the angles between the bonds being about 107 degrees apart (i think). because there are only 3 molecular bonds, we call the shape trigonal pyramidal. we apply the same logic to BF3 boron has 3 valence electrons each fluorine will form a single covalent bond with the central boron. so there will be 3 bonding pairs and 0 lone pairs, meaning 3 bonds total. that's the dot and cross for BF3 a molecule with 3 bonds will form a trigonal planar shape, with the bonds at an angle of 120 degrees. i don't believe that BF3 and NH3 have the same shape