Building Blocks
What is the tiny particle that makes up all matter and contains protons, neutrons, and electrons?
Atom
What is an element?
An element is matter made of only one type of atom; cannot be broken down by chemical means
Name two physical properties common to most metals.
Examples: shiny, malleable, good conductors (any two)
What is a molecule?
A group of two or more atoms bonded together
What is the center of an atom called, which contains protons and neutrons?
Nucleus
What are the vertical columns on the periodic table called, and what do elements in the same column usually share?
Groups (or families); they usually have similar chemical properties and same number of valence electrons
Which group (number) contains the alkali metals?
Group 1
What is the name for an atom that has gained electrons and carries a negative charge?
Anion
Which particle moves in electron clouds around the nucleus and has a negative charge?
Electron
Who is the scientist that organized elements into a table by observing patterns and predicting missing elements?
Dmitri Mendeleev
What is an alloy?
An alloy is a mixture of two or more metals (or a metal and another element) — e.g., steel
What is the name for an atom that has lost electrons and carries a positive charge?
Cation
What do we call atoms that have the same number of protons but different numbers of neutrons?
Isotope
What are periods on the periodic table?
Periods are horizontal rows across the table
Give two differences between metals and nonmetals (physical properties or conductivity).
Metals are shiny, malleable, ductile, and good conductors; nonmetals are dull, brittle, poor conductors, and have low densities
Describe how valence electrons are related to the formation of chemical bonds.
Valence electrons are the outer-shell electrons that are shared or transferred during bonding to fill outer shells and make atoms stable
Define "atomic number" and explain how scientists use it to identify an element.
Atomic number = number of protons in the nucleus; used to identify the element
Explain how the number of valence electrons changes as you move left to right across a period, and why that matters for reactivity.
Valence electrons increase left to right across a period; this affects how elements bond and their reactivity
Explain why noble gases (group 18) do not typically react with other elements.
Noble gases have full outer electron shells, so they are stable and do not usually react
Explain the difference between a molecule and a compound and give one example of each from the reading.
A molecule is any bonded atoms (e.g., O2); a compound is a molecule made of different types of atoms (e.g., H2O — water)