Oquizy

Xinyi investigates melting points of Period 3 elements. She notices Si has a much higher melting point than nearby elements. What best explains this observation?

Silicon contains free electrons. Silicon forms simple covalent molecules. Silicon has a giant covalent structure with strong bonds throughout. Silicon is a metal with giant metallic structure.

John compares sodium (Na) and potassium (K) in class. He notices they both form ions with a +1 charge. What explains this similarity?

They are in the same period. They have the same mass number. They have the same number of valence electrons. They have the same proton number.

The room floods with bromine water! John panics, but Xinyi stays calm. A screen appears: "Predict what happens when chlorine gas is bubbled through this bromine water."

Bromine gas is released No reaction Solution turns colourless Solution turns reddish-brown

The next puzzle shows melting points of three metals from the same group: 181°C, 98°C, and 63°C. The metals are Lithium, Sodium, and Potassium. Which metal corresponds to the lowest melting point, and why?

Lithium, because it's the smallest atom Potassium, because melting point decreases down Group I Potassium, because metallic bonding gets stronger down the group Sodium, because it's in the middle

Trying to impress Xinyi, John suggests wrapping the bike frame with aluminium foil to prevent rust. Which method of rust prevention does this represent?

Alloying Barrier protection Galvanization Sacrificial protection

Which statement best compares a halogen and a noble gas in the same period?

Both have the same number of electron shells and are equally reactive. The halogen has lower electronegativity than the noble gas. The halogen is more reactive because it has incomplete outer shell. The noble gas is more reactive because it has more valence electrons.

Quiz: Chemistry - Patterns In The Periodic Table