A technician reports that every atom in her sample holds exactly 26 protons in its nucleus, which is why the whole sample is iron. Which term names that count of 26?

In a model of a helium atom, two positive particles and two neutral particles sit packed in a tiny dense center, with the electrons far outside it. Which term names that center?

Two students burn magnesium ribbon in air; the gray metal and the oxygen gas join into a white powder that can only be broken apart again chemically. Which term names that powder?

A student shakes sand and iron filings together in a jar. Dark and pale grains stay visible side by side, and one scoop is not the same as the next. Which term describes the sample?

Silicon carries an electric current better than sulfur does but far worse than copper does, which is why it is used in computer chips. Which term names an element that behaves this way?

A model of a chlorine atom shows 17 electrons: two close in, then eight, then seven in the outermost shell. A chemist says those outer seven explain chlorine's reactions. Which term names them?

On a reagent bottle a student sees the two letters Fe printed directly above the word iron. Which term names Fe as it is used on that label?

An aluminum block and a lead block have exactly the same volume, but the lead block pulls its pan of the balance down hard. Which property of the two metals does this comparison show?

A student says the figure 65.38 printed under zinc's symbol tells him how many protons a zinc atom has. Which correction fits the way a periodic table box is read?

A student calls table salt an element because every grain of it looks the same all the way through. Which correction fits how matter is classified?

A student predicts that fluorine and chlorine react alike, and explains that this is because the two elements sit one above the other in the same period. Which correction fits the table?

A student writes that when she stirred 5 g of sugar into 200 mL of water, the water was the solute. Which correction fits the terms for a solution?

A student argues that the sugar water she stirred up is a compound, because she can no longer see any sugar in the glass. Which correction fits?

A student says that adding two electrons to a neon atom would turn it into magnesium, since magnesium sits two boxes further along the row. Which correction fits how elements are defined?

A lab report reads: 'The dark sand stayed on the filter paper while the clear liquid ran straight through, so the salt water that passed was a ___.' Which term completes it correctly?

A lab report reads: 'The copper wire lit the bulb but the lump of sulfur left it dark, so the property we compared was ___.' Which term completes the sentence correctly?

A lab report reads: 'Only 36 g of salt dissolved in 100 mL of water at 25 degrees Celsius; more salt just settled on the bottom. That measurement is the salt's ___.' Which term completes it?

A lab report reads: 'Each particle in our neon sample was the smallest piece that still behaved like neon, so every one of them was a single ___.' Which term completes the sentence?

A lab report reads: 'Lithium, beryllium and boron all sit next to each other along row 2 of the table, so these three elements share a ___.' Which term completes the sentence?

A lab report reads: 'Our copper strip is made of only one kind of atom, and no chemical change we tried broke it into anything simpler, so copper is classified as ___.' Which term completes it?