Chapter 4 Atoms And Element Flashcards
Define atom
A subatomic or submicroscopic particle that is the building block of matter
Define element
 A substance made up of only one type of atom
What is the atomic theory?
Each element is composed of indestructible particles called atoms. All atoms of a given element have the same mass and properties. Atoms combined in simple whole number ratios to form compounds.
Who was the first to propose the idea of an atom? And what did they believe?
JJ Thompson  and he believed that electrons were uniformly, distributed and present within the atom and in all elements
What was his plum pudding model
It was a description of an atom in which electrons are held in a loose sphere of positive charge or protons
Who tested JJ Thompson’s plum putting model
Ernest Rutherford with his Rutherford gold foil experiment
How did Ernest Rutherford test it?
So alpha particles were shot at atomic thin piece of gold, and were expected to pass through the loose fear of positive charge however, not all of the alpha particles pass through, and some are projected because of this Rutherford concluded that the atom must be made mostly of empty space with a dense positive center
What is the nuclear model of an atom?
Most of the atoms mass is positively charged and at the core known as the nucleus. Most of atoms volume is empty space in which electrons are dispersed. The atom is electrically, neutral, unless ions, which means the electrons equals the protons.
What was later added to the nuclear model of an atom
That’s a nucleus has positively charged in neutral charge, so protons and neutrons
What particles is the atom made up of mostly
The nucleus has majority protons and neutrons electrons contribute to the entirety of the atom not so much
Natural fundamentals of charge
Protons and electrons attract same charges, repel positive and negative charges will cancel each other out if they have the same magnitude
What are elements define by?
Their atomic number for the amount of protons in the nucleus they are also defined by their neutrons, but the neutrons vary
Who noticed the elements have similar
In 1865 Dmitri Mendeleev
What is the period Law?
What elements are arranged in increasing mass and increasing atomic number their properties occur periodically. Also elements in the same group or columns, behaves similarly
Where are metals and what other characteristics
Metals on the left side and the great conductors of heat and electricity, the malleable and ductile, and reactions they lose electrons
