SCIENCE 1ST QUARTER REVIEWER.pdf

SCIENCE JEFF CAYANAN | 1ST QUARTER Ad astra per aspera!!! =Lesson 1 - Framework for acquiring knowledge about the world through logical steps - Emphasizes objectivity and minimizes bias - Systemic process for investigating...

SCIENCE JEFF CAYANAN | 1ST QUARTER Ad astra per aspera!!! =Lesson 1 - Framework for acquiring knowledge about the world through logical steps - Emphasizes objectivity and minimizes bias - Systemic process for investigating 1. Observation the natural world - Noticing something in the natural world that sparks curiosity 2. Formulate a question - Navigating through the 1. Objectivity problem and find a solution - Reliable and unbiased - Questions should be clear, information using evidence focused, and researchable. and controlled experiments 3. Propose hypothesis 2. Reliability - Testable prediction that - Experiments can be provides a possible answer repeated - Usually started in an 3. Self correcting ‘’ if..then’’ should be - Build upon existing specific and measurable knowledge and refine our 4. Experiments understanding - Designing or conducting 4. Predictive power controlled tests to check - Make predictions about the validity of hypotheses future events - Collect empirical data that can confirm or refute the hypothesis 5. Data gathering Medical / pharmaceutical industry - Recording data from the - Developing new drugs or medical experiments procedures - Needs accurate/ systematic Agricultural industry documentation of - Improving crop yield through observations or enhanced planting method measurements to ensure Technology industry the data is reliable - Developing new softwares and 6. Data analysis machines - Determine if it supports or refutes the hypothesis - Drawing conclusions SCIENCE JEFF CAYANAN | 1ST QUARTER Ad astra per aspera!!! Lesson 2,3,4 1. Identify the atomic symbol of the - Hard, lustrous, malleable valence electrons - Good conductors of heat and 2. Write atomic symbol at the center electricity 3. Draw dots around the atomic symbol corresponding to the number of valence electrons. EXAMPLES: 1. Atomic symbol: P - Brittle, not lustrous 2. Valence electrons: 5 - Poor conductor of heat and electricity - Posses properties of both metal and non - metal - Good semiconductor that can - Maximum no. of valence electrons conduct a limited amount of that an atom can have is 8 electricity - They become less reactive and more stable like noble gasses - Valence electrons, located at the outermost shell. - Forces of attraction that holds - Atoms exist in an electron cloud atoms together by sharing - Visual representation of the - To achieve its most stable and valence electrons least reactive state - Composed of the atomic symbol of the element at the center and dots that represent each of the valence electrons in the element - H, He, Li,Be only required 2 valence electrons SCIENCE JEFF CAYANAN | 1ST QUARTER Ad astra per aspera!!! - Ionic 1. NaCl - Covalent - Metallic ANSWER = 2. MgBr₂ - Metal loses an electron to a non- metal through electron transfer forming an ionic compound - Ionic compound - High melting point and high boiling point - Conductor of electricity in matter/ aqueous state ANSWER = - Hard and brittle - Ionic formation 3. Al₂O₃ = - Electron transfer during ionic bonding forms. CATIONS (+) ANIONS (-) - Loses an - Gains an electron electron - Positively - negatively charged charged 4. Answer = 1. Draw respective LEDS of involved atoms 1. Write the chemical symbol of 2. Use arrows to illustrate transfer of involved elements electrons 2. Write the symbol for metals first, 3. Draw LEDS of the resulting followed by the nonmetal compound. Enclose each ion with 3. Write coefficients as subscripts if brackets there are any, if none your formula 4. Use superscripts to identify no. of is good to go electrons were gained/ lost E. G : Al F₃ = AlF₃ 5. Use coefficients to identify no. of Li Ci = LiCi atoms involved. Ca Cl₂ = Cacl₂ SCIENCE JEFF CAYANAN | 1ST QUARTER Ad astra per aspera!!! - Two pairs of electrons is shared by two atoms - Two pairs of electrons is shared by 1. Write the name of the cation first two atoms 2. Write the root name as the Anion 3. Triple covalent bonds (non-metal) and add the suffix ‘’-ide’’ - (≣) (6 electrons) 3. Note that only the first letter of the - Three pairs of electrons is shared cation’s name is capitalized by two atoms E.G: LiCi = Lithium Chloride NaI = Sodium Iodide - Add total numbers of all the - 2 non metal atoms share one or elements more electrons to reach stability - Arrange the given by placing the - electrons are not transferred least electronegative as the central atom and the remaining atoms around it (except H and He) keep the structure as symmetrical as possible - Connect all atoms using one single - Low melting and boiling point covalent bond - Poor conductor of heat and - Subtract 2 electrons for every electricity single bond that was formed - Generally soft - Add some pairs to complete the - How does it happen? octet for each atom in the structure - Able to gain electrons and - If there are not enough electrons to are incapable of losing complete the octet.. Form multiple them bonds - Check if all atoms fulfill the octet rule. E. G: 1. Single covalent bond - (-)(2 electrons) - Only one pair of electrons is shared by two atoms 2. Double covalent bond - (=) (4 electrons) SCIENCE JEFF CAYANAN | 1ST QUARTER Ad astra per aspera!!! - Write the chemical symbol of the NO. PREFIX involved elements. Write the 1 Mono symbol of the less electronegative 2 Di first, followed by the element that 3 Tri has more electronegatives 4 Tetra - Identify the number of atoms in 5 Penta each element using subscripts, if 6 Hexa there is only one atom present in 7 Hepta 8 Octa an element, do not write any 9 Nona subscripts 10 deca - E,G: PFვ - Among metals wherein there is a - Write the name of the least collective sharing of a sea of ve. electronegative element first - How does it happen? - Write the root name of the second - When metals form metallic bonds, element and place the suffix ‘’ide’’ their respective ve becomes - Use greek prefixes in the identity ‘’delocalized’’ forming a metal The number of atom (s) cation and a sea of electrons - phosphorus trichloride - Baron difluoride - Sulfur pentoxide High density - Metals are tightly packed. - Many particles occupy a small volume High melting and boiling point - Hydrogen will always be written - Large amounts of energy in forms of before any element that belongs to heat to be broken. the group 6 and 7. Otherwise Malleability hydrogen will be written after - Can be hammered into thin sheets - Rearranged but the bond doesn't break. Ductility - Can be drawn into wires - Rearranged but the bond doesn't break Lustrous - Ability to reflect light SCIENCE JEFF CAYANAN | 1ST QUARTER Ad astra per aspera!!! 1. Based on type of element Metal + Non-metal = Ionic ELECTRONEGATIVITY TYPE OF Non-metal + Non-metal = covalent DIFFERENCES BOND Metal + metal = metallic ⛰EN ≥1.7 IONIC BOND 2. Electronegativity POLAR - Ability of an atom to attract electrons 1.7 ＞⛰EN ＞O.4 COVALENT - Higher ability - stronger ability to NONPOLAR gain - Differences influences the polarity of a compound or the distribution ⛰EN ≤ O.4 COVALENT of electrical changes of the compound In simpler terms… 3.Polarity and electronegativity The electronegativity is greater than or - Ionic compound equal to 1.7 = IONIC - A complete transfer of electrons The electronegativity is between 0.4 and positive/ negative ends of the 1.7, not including 0.4 and 1.7=COVALENT compound The electronegativity is less than or equal Covalent: to 0.4.= NON-POLAR - Unequal sharing of shared electrons - One atom pulls the electron more than the other Polar covalent: - Unequal sharing of electrons - Partially positive end and partially negative end Nonpolar covalent: - Equal attraction for the shared electrons - Electrons are pulled equally