Scientific Method
It's the testable, educated prediction about the outcome of an experiment, often written as an "If... then..." statement.
What is a hypothesis?
Derived from its Latin name natrium, this soft, highly reactive alkali metal in group 1 goes by this two-letter chemical symbol.
What is Na?
In a Bohr model of an atom, electrons orbit the nucleus in discrete energy levels, with the maximum number of electrons in the innermost shell capped at this number.
What is 2?
Required in almost every lab handling chemicals, this piece of eyewear protects against liquid splashes and flying debris.
In Chapter 1, a NASA deep space probe launched in 1977 is highlighted for maintaining a constant speed of about $55,000 km/hr without engine power, illustrating Newton’s First Law
What is voyager 1?
In a classic experiment testing how sunlight affects plant growth, this is the name given to the amount of light, because it is the factor the scientist intentionally changes.
What is the independent variable?
While columns in the periodic table are called groups or families, these are the name given to the seven horizontal rows.
What are periods?
When drawing the Lewis dot structure for neutral Carbon (group 14), you place exactly this number of dots around its chemical symbol.
What is 4?
If hazardous chemicals splash directly into your face, you should immediately head to this station and flush your eyes for at least 15 minutes.
What is an eyewash station?
Chapter 2 opens with a quote from this famous Italian astronomer: "In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual".
Who is Galileo Galilei?
To ensure a fair test, scientists keep these factors identical across all experimental groups—such as room temperature, pot size, and soil type.
What are controlled variables (or constants)?
Argon, neon, and helium belong to this group on the far right of the table, so named because their full valence shell makes them almost entirely unreactive.
What are the noble gases?
While a Bohr model illustrates all electron shells surrounding an atom's nucleus, a Lewis dot structure exclusively depicts these outermost electrons involved in bonding.
What are valence electrons?
Toxic, volatile, or smelly chemical reactions should always be conducted inside this enclosed laboratory workstation that draws airborne hazards away from the user.
Hint: We do not have one.
What is a fume hood?
Featured on page 7, this English scientist created iconic, hand-drawn circle symbols to represent chemical elements in his 1808 work A New System of Chemical Philosophy.
Who is John Dalton?
Popularized by philosopher Karl Popper, this key requirement of any valid scientific hypothesis states that it must be theoretically possible to prove it wrong.
What is falsifiability?
Decreasing as you move down a group and increasing as you move left to right across a period, this property measures an atom's ability to attract shared electrons in a chemical bond.
What is electronegativity?
When drawing Lewis structures for molecules like ammonia (NH3) or water (H2O), non-bonding valence electron pairs left over on the central atom are called by this two-word term.
What are lone pairs (or unshared pairs)?
When mixing acid and water, chemical safety rules dictate you should always add the acid to the water rather than water to the acid to avoid this violent phenomenon.
What is splattering (or an exothermic reaction / heat release causing boiling)?
This sea creature is profiled in Chapter 2 for storing remarkable concentrations of heavy metals like vanadium in its blood cells.
What is a sea squirt (or tunicate)?
To eliminate researcher bias, clinical drug trials often use this experimental design where neither the patients nor the doctors evaluating them know who received the active treatment versus a placebo.
What is a double-blind study?
When Russian chemist Dmitri Mendeleev published his periodic table in 1869, he successfully predicted the existence and properties of this element, temporarily giving it the provisional name "eka-aluminum."
What is gallium?
Niels Bohr incorporated this 1900 Planck concept into his atomic model to explain why electrons only occupy specific, fixed orbits rather than spiraling into the nucleus.
What is quantization (or quantized energy levels)?
This standard document provided by chemical manufacturers outlines an element or compound's hazards, safe handling procedures, and emergency spill measures.
What are Safety Data Sheets (SDS). Formely MSDS.
Chapter 2 concludes its discussion on historical evidence with this famous 5,000-year-old ice mummy discovered preserved in the Ötztal Alps.
Who is Ötzi the Iceman?