Chapter 1 – Atoms and Elements Flashcards
(20 cards)
What is the atomic number of an element?
The number of protons in the nucleus of an atom.
In a neutral atom, what is the relationship between protons and electrons?
They are equal in number.
Where are protons, neutrons, and electrons found in the atom?
Protons and neutrons are in the nucleus; electrons orbit around the nucleus.
What is the simplified formula to find the number of neutrons in an atom?
Atomic mass - Atomic number = Number of neutrons
What does the periodic table organize elements by?
By increasing atomic number and chemical properties.
What are valence electrons?
Electrons in the outermost energy level of an atom.
What is the Rutherford-Bohr atomic model?
A model showing protons in the nucleus and electrons in fixed orbits around it.
What do all elements in a group (column) on the periodic table have in common?
The same number of valence electrons.
What are the properties of metals?
Conduct heat and electricity, malleable, ductile, shiny, usually solid at room temp.
What are the properties of non-metals?
Poor conductors, often gases, brittle when solid.
What are metalloids?
Elements with properties of both metals and non-metals.
What is a period in the periodic table?
A horizontal row; indicates the number of electron shells.
What is a family/group in the periodic table?
A vertical column; elements have the same number of valence electrons.
Describe alkali metals (Group IA).
Soft, very reactive, 1 valence electron, not found pure in nature.
Describe alkaline earth metals (Group IIA).
2 valence electrons, reactive, not found pure in nature.
Describe halogens (Group VIIA).
7 valence electrons, very reactive, form salts and acids.
Describe noble gases (Group VIIIA).
Full outer shell, stable, non-reactive.
What is ionization energy?
The energy needed to remove a valence electron.
What is electronegativity?
The force with which an atom attracts electrons.
What happens to atomic radius across a period and down a group?
Decreases across a period, increases down a group.
