HH Science

subatomic particles location

Proton (charge of +e, in the nucleus), Neutron (0 charge, in the nucleus), and Electron (charge of -e, outside the nucleus).

Charges of subatomic particles

Proton: + Electron: - Neutron: neutral

What is the left side of the equation called? reactants or products?

REACTANTS! The substance(s) to the left of the arrow in a chemical equation are called reactants. A reactant is a substance that is present at the start of a chemical reaction.

Where are the least reactive elements found (left or right side)?

RIGHT! The reactivity of the elements increases going from left to right on the periodic table. Each element going from left to right tends to be more reactive. But, at the far right are the noble gasses, and they are almost completely inert.

physical vs chemical properties

A physical property is an aspect of matter that can be observed or measured without changing it. Examples of physical properties include color, molecular weight and volume. A chemical property may only be observed by changing the chemical identity of a substance. Physical- melting & boiling point, solubility, odor, color and density Chemical- reactivity of molecules resulting in change in composition

Matter

Anything that has mass and takes up space

What determines if molecules form?

Atoms come together to form molecules because of their electrons. Electrons can join (or bond) atoms together in two main ways. When two atoms share electrons between them, they are locked together (bonded) by that sharing. These are called covalent bonds.

Atoms

Building blocks of matter

How does the periodic table arrange elements

By proton number

What do coefficients tell us in a chemical equation?

Coefficients are used in all chemical equations to show the relative amounts of each substance present. This amount can represent either the relative number of molecules, or the relative number of moles.

what does an atom look like?

In order to clearly visualize atoms, a scanning tunneling microscope is used which is a microscope that uses electrons instead of light to see very small objects. The resolution of these microscopes is good enough so that individual atoms can be seen as bumps. ... All atoms will scatter some of the light that hits them.

Why is the valence shell important?

It determines many of an atoms chemical properties

Where are the most reactive elements on the periodic table (left or right side)?

LEFT! The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive. Lithium, sodium, and potassium all react with water, for example.

What is an element?

a Substance that contains only ONE type of atom.

physical vs chemical change

physical only state of matter change chemical change substance into new thing. but no molecules lost

Molecules

Groups of two or more atoms held together by chemical bonds

examples of common molecules

H2O (water) N2 (nitrogen) O3 (ozone) CaO (calcium oxide) C6H12O6 (glucose, a type of sugar) NaCl (table salt)

how many electrons can fit on each valence shell?

Number of electrons in each shell — Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on.

What is the right side of the equation called? reactants or products?

PRODUCTS! The substance(s) to the right of the arrow are called products .

What does the "group" tell us about an element?

The group number in the periodic table represents number of valence electrons of the elements in a certain group. For example, all the elements in Group−1 have 1 electron in their outer most shell.

valence shell

The outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom.

Where are all elements organized?

The periodic table of elements arranges all of the known chemical elements in an informative array. Elements are arranged from left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass. The rows are called periods.

what does the periodic table symbol tell us?

The symbols are abbreviations of the origins of the word for each element. For example, the origin of lead's symbol, Pb, is the Latin word 'plumbum' meaning 'liquid silver'.

What do subscripts tell us in a chemical equation?

e use subscripts in chemical formulae to indicate the number of atoms of an element present in am molecule or formula unit.

law of conservation of matter?

matter is neither created nor destroyed, so we must have the same number and type of atoms after the chemical change as were present before the chemical change.

What does the atomic number represent?

number of protons

What does the atomic mass represent?

protons + neutrons

subatomic particles that make up atoms

protons, neutrons, electrons

element symbol

the abbreviation of an elements name; 1 or 2 letters, first letter is always capitalized, second is never capitalized