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100

This is the central part of an atom, containing protons and neutrons.

What is the nucleus?

100

This is the smallest unit of an element that retains its chemical properties.

What is an atom?

100

This is the weighted average mass of an element’s isotopes.

(What is atomic mass?)

100

This negatively charged particle orbits the nucleus and is involved in chemical bonding.

What is an electron?

200

This particle in the nucleus of an atom has no charge and helps stabilize the nucleus.

What is a neutron?

200

This positively charged particle is found in the nucleus of an atom and determines the element’s identity.

What is a proton?

200

This number represents the total protons in the nucleus of an atom and identifies the element.

What is the atomic number?

200

This is an atom or group of atoms with a net positive or negative charge.

What is an ion?

200

This is an ion with a positive charge formed when an atom loses electrons.

What is a cation?

300

This refers to patterns in properties of elements, such as electronegativity or atomic radius, across periods or groups on the periodic table.

What is a periodic trend?

300

This property measures an atom's ability to attract electrons in a chemical bond.

What is electronegativity or electron affinity?

300

This describes how easily an atom can lose electrons to form positive ions, and it increases down a group.

What is metallic character?

300

This is the distance from the nucleus to the outermost electron of an atom.

What is the atomic radius?

300

This is a variation of an element that has the same number of protons but a different number of neutrons.

What is an isotope?

400

This is the energy required to remove an electron from a neutral atom.

What is ionization energy?

400

This is a vertical column on the periodic table where elements share similar properties.

(What is a group?)

400

These regions around the nucleus describe the probable location of electrons and are designed by the letters: s,p,d, and f.

What are orbitals?

400

This is a horizontal row on the periodic table where elements increase in atomic number.

What is a period?

500

This phenomenon occurs when an unstable nucleus emits particles or energy to become more stable.

What is radioactivity?

500

This property of a nucleus depends on the ratio of neutrons to protons and determines if the nucleus will undergo decay and transform into another element.

What is nuclear stability?

500

This is an ion with a negative charge formed when an atom gains electrons.

What is an anion?

500

This heavy element, with the symbol Pb, is often used to block radiation cause it is the largest stable element

What is Lead?

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