Science Test 4-23-17

Hydrogen: 1 ve. Colorless, Odorless, gas. Low density. Most abundant element. Ex. Stars.

1 ve. Colorless, Odorless, gas. Low density. Most abundant element. Ex. Stars.

Metallic Bonds are formed between:

2 metals.

Covalent Bonds are formed between:

2 nonmetals.

Explain the main reason so many different molecules are made from carbon atoms:

4 ve, so 4 bonds, making big molecules.

How many elements were on the original periodic table?:

63.

Metallic Bond:

A bond formed by the attraction between positively charged metal ions and the electrons around them.

Covalent Bond

A bond formed when atoms share one or pairs of electrons.

Ion:

A charged particle that forms when an atom transfers electrons.

Molecule:

A group of atoms that are held together by chemical forces; the smallest unit of matter that can exist by itself and retain all of a substance's chemical properties.

Electron Dot Diagram/Lewis Structure:

A model that shows only the valence electrons of an atom. Used to show how atoms bond in molecules.

Valence Electron:

An electron that is in the outer shell of an atom and determines the atom's chemical properties.

Hologen:

An element in group 17. Combine with most metals to form salts. Very reactive nonmetals. Insulators. 7 ve. Get one electrons from metals.

Noble gas:

An element in group 18. Unreactive. Colorless, odorless, gasses.

Alkaline-earth metal:

An element in group 2. Reactive. Silver, higher density, 2 electrons in outer level. Ex. Airplane parts, chalk, cement.

Chemical Bond:

An interaction that holds atoms or ions together. Bond that forms when two atoms join.

What did scientists begin using in 1914?:

Atomic numbers, or the number of protons in an atom.

What three things can happen to electrons when a bond forms?:

Atoms can gain, lose, of or share valence electrons to form a chemical bond.

Who typically forms covalent bonds?:

Atoms of nonmetals.

Ionic Bond:

Complete transfer of valence electrons between atoms. A chemical bond that generates two oppositely charged ions.

Three properties of metals that are caused by metallic bonding:

Conductibility, Ductility (stretchy), malleability

Which type of substance would you use as insulating material for a hot mitt?:

Covalent bonds, because they're nonmetals.

Covalent bonding only:

Covalent; two or more atoms share electrons, low melting points, between 2 nonmetals, gas or liquid, insulators, can have double or triple bond, interaction between neutral atoms.

Mendeleev:

Created the organization of the periodic table. Arranged the elements in increasing atomic mass, and found gaps which led to the discovery of new elements.

Ionic compounds are bonded in a three-dimensional pattern called a:

Crystal lattice.

What is listed in each square on the PTE?:

Element's atomic number, symbol, name, and atomic mass.

In which part of a pencil are metallic bonds found?:

Eraser.

Alkali metal:

Group 1. Most reactive. Forms compounds easily, giving away an electron. Reacts with water and oxygen. Soft, shiny, silver, low density. Ex. Table salt.

Period:

Horizontal rows in the periodic table. Goes by atomic number. Elements in the same period have the same electron shells.

What makes atoms more or less willing to be bound?:

How many valence electrons an atom has determines its reactiveness. Atoms bond to fill their outermost energy shells, it's more stable that way.

-Smashing something into a million pieces is:

Ionic

Compare the three types of bonds based on what happens to the valence electrons if the atoms:

Ionic they lose, covalent they share, and metallic they are free (which gives them their properties) overlapping, flowing freely.

Ionic Bonding only:

Ionic; atoms gain/lose electrons, between non-metal+metal, high melting points, conductors, interaction between Cations Anions. Solid. Positive or negative charges.

Periodic Law:

Law states that the repeating chemical and physical properties change periodically with the atomic numbers of the elements. Groups.

Properties of molecules:

Low melting and boiling points (not water), one compound can be found by itself in a reaction, gasses at room temperature, and when a solid usually soft.

Two properties of covalent compounds?:

Lower melting points, insulators, nonmetals, gases.

How is Moseley's basis for arranging the elements different from Mendeleev's?:

Mendeleev came up with the pt, and put it by atomic mass. Moseley changed it to atomic number.

What type of element tends to lose electrons when it forms bonds?:

Metal

Differences between Metallic bond material properties and Covalent bonds:

Metallic; conductive, malleable, ductile, stronger than the graphite. Covalent; soft, graphite (soft), erasers.

Similarities between Ionic and Covalent Bonds:

Molecules, both use nonmetals, weak when solid, both bonding, both involve ve.

How many elements had scientists arranged by the 1860's?:

More than 60.

Metals:

Most elements. Few electrons. Solids at room temperature. Shiny, ductile (stretchy), conductors, malleable. Left on periodic table.

Nonmetals:

Nearly full outer level. Gases at room temp. Not malleable, ductile, or conductors. Are brittle. Bond with a metal. Right on periodic table.

In Ionic Bond, Nonmetal accepts those electrons to become a:

Negatively charged anion.

Inert gases:

Noble gases, group 18. Full outer shell, so unreactive. Colorless and odorless.

Why are valence electrons significant?:

Only the electrons in the outer shell are able to form bonds.

Metalloids:

Outer level is half filled. Has properties of both other classes. Brittle and a conductor. Found on zigzag line on the periodic table.

In Ionic Bond, Metal loses electrons to become a:

Positively charged cation.

Diatomic Molecule:

Simplest molecules, made up of only two bonded atoms.

What did Mendeleev find out?:

That elements can be predicted based on their properties. Better atomic mass measurements would lead to better predictions.

How does the periodic table help you determine valence electrons?:

The atoms of all the elements in a group have the same number of valence electrons.

Why do atoms form covalent bonds?:

To fill outer energy shell, the attraction holds the atoms together.

Molecule Example:

Two hydrogen atoms form a covalent bond, and the result is a hydrogen molecule.

Lanthanides and Actinides:

Two rows at the bottom of the table. First row, L, mixed with metals to increase strength. Next row, A.

What does metallic bonding allow for?:

Valence Electrons can move throughout metal, keeps the ions together, canceling the ions' positive charge. Allows metals to conduct electricity. Metals are used to make wires. Atoms in metals can easily be rearranged. The movement maintains the metallic bonds.

Group:

Vertical rows in the pt. Elements in a group share similar chemical properties. Families. Same amount of valence electrons.

Chemical Bonding:

When atoms join together to form molecules or ionic compounds.

When do chemical bonds form?:

When electrons in atoms interact.

How do atoms form chemical bonds?:

When electrons in atoms interact. Share gain or lose electrons with another atom.

Diatomic Element:

When the two bonded atoms are of the same element.

The alkali metals and the halogens are the most reactive elements on the pt. Why?:

When they make compounds they give away one of their electrons.

List three materials that are composed of molecules that have covalent bonds:

Wood, lead, steel, eraser.

Can atoms of the same element bond together?:

Yes. Double bond.