science test :(

Covalent Bonding: 

What makes an atom stable?

By having a full set of valence electrons

Covalent bond- atoms bond by sharing valence electrons and completing each other

Ionic Bounding:

Ion- a charge based on an imbalance of protons to electrons

Ionic Bond- a bond formed by the attraction of opposite charged ions

When is an atom not an ion?

When they are not charged

(When Halogens need one more valence electron, they take one from another atom, which gains the Halogen their one and makes the atom lose theirs. This makes them charged and attracted to each other.)

Alkali Metals- are not stable and only have one electron.

Alkali Earth Metals- 2 valence electrons and more stable than alkali metals but still unstable

Transition Metals- Active metals, semimetals, and non-metals serve as a bridge between the two sides of the table (stable).

Halogen- an atom that has 7 valence electrons and can take valence electrons called electronegativity

Noble Gases- stable and have a full set of valence electrons

Hydrogen- only one valence electron (stable) but will hook up/ connect with almost anything.

Atom, Element, Molecule, and Compound:

Atom- single unit of matter that cannot be broken down further

Element- a bunch of the same atoms together (unbonded)

Molecule- 2 or more atoms bonded together

What is it called when 2 of the same atoms bond together?

Homonuclear Diatomic Molecule

What is it called when 2 or more different atoms bond together?

Compound

Chemical Reaction vs Physical Reaction:

When molecular bonds break and atoms rearrange differently, making new substances 

Signs of chemical reaction

• Instant bubbles 

• Instant temperature change

• A precipitation forms

• Instant color change 

• odor

Physical Reaction - A change in appearance, but molecules are the same.

Law of Conservation of Mass/Matter:

Law of Conservation- in every chemical reaction, no atoms are lost nor gained. Matter is neither created nor destroyed. Atoms are just being recycled.

What is it called when you balance chemical equations?

Stoichiometry

Energy in Chemical Reactions:

What is between the bonds between molecules?

Energy

When molecules break apart, energy is released. That energy is used to reassemble the atoms and make new molecules.

PH- potential of hydrogen

What pH level makes an acid?

0-6.99

What pH level makes a base (alkali)?

7.1-14

What pH level is natural?

7

What can determine pH?
Red cabbage

What is natural?

Water

What is the taste of acids?

Sour

What is the taste of bases?

Bitter 

Endothermic VS Exothermic 

What energy is not enough to complete the change, so energy is absorbed from the environment?

Endothermis

What energy is too much after the change is complete? Energy is released into the environment.

Exothermis

Is melting ice endothermic or exothermic?

Endothermic

Is photosynthesis endothermic or exothermic?

Endothermic

Is water evaporation into gas endothermic or exothermic?

Endothermic

Are fireworks endothermic or exothermic?

Exothermic

Is water turning into ice endothermic or exothermic?
Exothermic

Are hand warmers endothermic or exothermic?

Exothermic

Natural VS Synthetic 

 What is synthetic? 

Synthetic is something that is not natural but starts from natural materials?

What is natural?

Something that comes from nature.

Is artificial sweetener synthetic or natural?

Synthetic

Are vegetarian burgers synthetic or natural?

Natural (if all plant-based) synthetic (if it has a meat substance that is not natural)

Are McDonald's burgers synthetic or natural?

Synthetic (the stuff in McDonald's bugers is NOT natural)